PDA

View Full Version : Fitting a 70hp Jono



Hornet Rider
02-08-2008, 07:13 PM
FNQ, others - I've replaced my 1990 Evinrude 50hp with a 1998 Jono 70hp on a 17ft tinny. Son & I bolted it on today. Have gone one set of holes higher than where the 50hp was bolted. Pics below show where it is sitting. Appreciate anyones comments on mounting height. The water testing will reveal most of the answers, so next step is to fit-out the electrics, tacho etc then get it onto the water to see what's what.

FNQ - took your advice & went one hole up. Need to now determine which prop will give me what I need.


Quote:
Originally Posted by Hornet Rider http://www.ausfish.com.au/vforum/images/buttons/viewpost.gif (http://www.ausfish.com.au/vforum/showthread.php?p=868349#post868349)
FNQ, while your waiting for steve to get back to you with his measurements, just how far should the cav/vent plate be about the bottom of the hull? I'm about to replace my evinrude 50 with a jono 70. Pic shows current height of existing 50 hp, so I was going to replicate that same height on the 70 when I fit it.


HR as high as you can get it without undue negatives, the degree to what constitutes a negative will be different for each person, on average a ski boat will be set lower than a fishing boat due to the need to execute tight turns.

Low V and light can mean 5mm above the bottom is too high, deeper V and heavier hulls can often go higher, regardless testing is the only way to find out what suits your individual setup.

Foils can rob near an entire inch of Pitch from the prop whenever it is being dragged through the water so to make them work without this big negative the engine needs to be as high as possible so they clear the water as early as possible. Often it's not possible to get the engine high enough without too much ventilation.

Yours looks close to the bottom but it's hard to tell from the pic, try up one hole, if it works try another, I notice there is no room to drop it so up might be worth a test.

cheers fnq

Scalem
03-08-2008, 06:04 AM
I have a year 2000 Jonno ( grey cowl) and recently re-propped her. I never would have beleived a prop would make such a huge difference to the over all behavior of the boat, but it has.

By the look of the photos you have the same "original" OMC prop that I have, which is now in the garden shed, probably never to be used again unless absolutely necessary.

I went from the 14" x 17P original stainless to a solas x 17P stainless, I am not sure if it is the 13.25" or the 13.75", but am now enjoying what I consider to be the perfect match to the motor. My WOT revs went from 4800, and the motor was struggling to go any faster than 46k, to 5300 and 55k, and the motor is not breaking down at peak revs.

One thing I noticed was how much further away the props' blades are to the trim tab on the leg. THe new prop is certainly in cleaner water which helps overall performance. I think I would start with a test prop from Solas on the sunshine coast before committing to a transom height adjustment. And I would do it in that order, not the other way around.

Scalem

Chimo
03-08-2008, 08:18 AM
Hi HR

The height as you have it looks about right for the type of boat.

I fiddled with my 90HP height on a 5.6 and found almost as far up as possible was good and that if you use a foil (I had the shark two piece unit) you need to be able to trim the motor back and up at speed to the point that resulted in the foils being at a height you could fit your flat hand between the bottom of the foil and the water surface at high speed. This gave you lift and low speed (motor trimed in ) and resulted in no drag and top efficiency and speed at the top end. There is enough bouyancy and good length to boat width ratio in the express to not have to worry about broaching in following seas or when playing in the surf.

One thing I did find is that the bouyancy of salt water vs fresh is significant and in salt it was possible to get cavitation in tight turns at speed while this was not the case in fresh. Based on that I figured I had it about right, as it wasn't a ski boat, and I was looking for optimum point to point economy and performance. I had a SS OMC prop on mine and a spare al that I never used in 9 yrs.

Yours looks about right and if it were mine I'd leave the prop you have and have a go before worrying about changing it. On the size boat you have you may not need a foil althogh it will plane at even lower speeds which would be handy in rough sea conditions.

Sorry we couldn't catch up the other day but figured you would have had a long day as it was.

Cheers
Chimo

Hornet Rider
03-08-2008, 08:48 AM
Scalem, thanks for that. Interesting stuff this playing with props & engine height. The Seloc repair manual I've got quotes WOT of 5000-6000 rpm for 70hp 1996- 2001 models, with a minimum test rpm of 5700. So with your new 13.25 or 13.75 x 17 you've still got 700 rpm spare under WOT. Looks like you're getting the performance you want & your motor isn't struggling, being over worked & has spare rpm. Good outcome.

The prop on the 70hp we fitted yesterday is a standard OMC 13.25 x 17. That seem to align with OMC & Solas figures for matching prop & boat. The boat has a low deadrise of about 8 degrees, 300kgs hull, 120kgs motor/steering gear, 74lts full fuel & usually on 2 adult males, with say another 50kgs for safety gear, esky, fishing gear etc. Say about 700kg on the water with full fuel.

I went one hole up on fitting to see what the height difference might result in. If it performs like a dog, then I will drop it a hole & re-test. I'd be surprise if it doesn't perform well as is, but we'll see. Was just interested in any feedback on the height it's currently at, as the pics show.

FNQCairns
03-08-2008, 08:54 AM
Looks good HR! but as you say a water test will tell you what's going on. As you probably know it's easy to change the height at the ramp on the trailer using the jocky wheel to select the next hole up or down.

Mate it's going to go like a scalded cat! with that extra 20hp.

What prop is on it atm? although spending a single cent on a prop is a waste of money until you test with the prop you have.

Scalem, your increase in performance is due to the diameter change not the brand, you still have a little way to go, looks like you might be a candidate for an engine lift and/or a slight decrease in diameter to hit the finish line. Many wil never bother though as it is good enough.

cherrs fnq

Hornet Rider
03-08-2008, 09:05 AM
Hi Chimo, good to hear from you. Thanks for letting off the visit list last week. Got thru your area about 6.30pm, despite the traffic, but was bleary eyed & needed to RV with my son to unload the 70hp from the trailer. We'll catch up in time. I've gotta see your Vag! Thanks for the feedback on the motor height & performance tips. Agree on leaving the existing prop as is & see how the express performs. I'm thinking it should go reasonably well, if not better. The real question is will it need a foil? I want that same performance I was getting out of the 50hp with it foil - up on the plane at almost not revs & that warm fuzzy feeling in a big following sea. I'd like to see it actually go a bit over 6000 rpm at WOT, then I'll know I'll have a couple of hundred rpm up my sleeve if really need to get me out of the clag in a big chop. I figure we may be on the water in 2 weeks. Will keep you posted.

Saw the Malaysian express bit. Very interesting. I wonder what the built quality is. Also saw the great rap Black Jenny gave you - well deserved.

regards, HR

Hornet Rider
03-08-2008, 09:16 AM
FNQ - scalded cat, love it. She's currently named the HUNEB (honey bee). Might have to rename her SUPAB. As you'd appreciate, the upgrade isn't about going faster, although as a bi-product that will be handy. The 50hp I replaced is in excellent nick, regular 100 hourly services, nothing wrong with it but just that I wanted a bit of extra grunt for getting back from wide, especially if the weather turns & that increased responsiveness when surrounded by nasty chop, or bar crossing.

You probably read above - it's a standard OMC 13.25 x 17, we'll go with that & see what happens. Appreciate you tips on height & will keep you posted.

Chimo
03-08-2008, 09:58 AM
HR

If your talking to David P it would be interesting to get some feedback on the Malaysian story. They make the Air Berths there and they are pretty good so I doubt there would be an issue with the quality of the assembly of the express. Lochie may have some comments too.

Cheers
Chimo

FNQCairns
03-08-2008, 01:18 PM
FNQ - scalded cat, love it. She's currently named the HUNEB (honey bee). Might have to rename her SUPAB. As you'd appreciate, the upgrade isn't about going faster, although as a bi-product that will be handy. The 50hp I replaced is in excellent nick, regular 100 hourly services, nothing wrong with it but just that I wanted a bit of extra grunt for getting back from wide, especially if the weather turns & that increased responsiveness when surrounded by nasty chop, or bar crossing.

You probably read above - it's a standard OMC 13.25 x 17, we'll go with that & see what happens. Appreciate you tips on height & will keep you posted.

Hope fully the 13.25x17 will do it for you it's a great prop and suited to so many of our lighter/lower powered fishing boats, your new cruising speed will be near your old engines top speed;D.


cheers fnq

Scalem
03-08-2008, 09:09 PM
Scalem, your increase in performance is due to the diameter change not the brand, you still have a little way to go, looks like you might be a candidate for an engine lift and/or a slight decrease in diameter to hit the finish line. Many wil never bother though as it is good enough.

cherrs fnq

With talk of scalded cats and even more top end speed, it has me wondering how much faster this baby will go.:o My service agent told me how he ran the same motor on a very light race hull with a smaller diameter race prop. The revs he was pulling was obscene!! But he said, WTF, I am a mechanic, if she blows, she blows. After racing he inspected the motor thoroughly - no harm done at all.

So I guess I can get even more performance, but my hull is only a 4.3mtr glass runabout , so I think 5300rpm is plenty for me. I don't want to lose my undies ( like the add on TV recently);D ;D

Scalem

Hornet Rider
04-08-2008, 07:30 PM
Out of interest Scalem, what kind of boat is it, & what does it weigh?

Scalem
04-08-2008, 09:13 PM
Out of interest Scalem, what kind of boat is it, & what does it weigh?

Photo attached - I have a new trailer under her now, but the boat is unchanged.

Don't know what she weighs, never have done that, but no brakes on trailer means under 750kg I suppose..... Probably around the 600kg???

Scalem

Hornet Rider
05-10-2008, 03:59 PM
First test run yesterday after fitting the 70 johno. Has a standard OMC 13.25 x 17P, & SE Sport 300 foil. Engine height as per pics below. Didn't turn in the figures I'd expected. OMC say WOT should be 5000-6000 with 5700 at best engine set-up. This is what I got yesterday:

WOT 5300 with top speed of 52kph, fuel consumption 0.6ltr/km (1.6km/ltr)

With 3 up (850kg) from the 50 evinrude I replaced with this 70 johno, I'd get 0.4 ltr/km (2.5km/ltr)

Thought it would spring out of the hole but despite a good amount of acceleration from a standing start, & only 8 degrees dead rise, it climbed out of the hole slowly. Steering was positve at all speeds & no ventilation on high speed turns with motor trimmed about 1/2 out. Half as quiet as the 50 evinrude & noticable more lower torque.

Not satisifed with a WOT of 5300 when 5700 is the minimum target WOT, preferablay 6000. Question is do I lift the motor another notch or do I experiement with props? Any ideas?

Chimo
05-10-2008, 04:15 PM
Hi HR

I found on a 5.6m with a 90HP that the motor was at the right height when it would cavitate a little in tight turns but run fine in a straight line in sea water. At the same height it would run without cavitation straight and in turns in fresh water. Also had foils on the motor that obviously were above the surface with the motor trimmed up / out for high speed cruising / running.

Good to see to see your having fun with it.

Cheers
Chimo

disorderly
05-10-2008, 04:27 PM
HR .....

Without hijacking your thread...I'm wondering if someone can enlighten me about motor height....looks you you have some work to do to lift those RPM's.

When a heavier replacement engine is placed onto an older tin, low deadrise hull and the hull sits lower in the water at rest and until the boat is planing....should the motor be raised higher than the generally accepted standard.. ?

At what height does the motor lose clean water when the cav plate is raised higher than the bottom of the hull...?

Scott

Hornet Rider
05-10-2008, 04:40 PM
Chimo, how's things? Yes the fun continues. Note your points about ventilation on turns & I'm thinking the next move is to go ahead & raise it the last notch. It's a fishing boat after all, not a speed boat, so multiple tight turns at speed aren't that important.

Disorderly, Scott, don't know the exact answer either but it does sit lower at rest. It's about an extra 28kg to the 50 evinrude so that's why I put it up 2 notches when I fitted it.

..... back to the shed looking for 400 or more rpm::)

FNQCairns
05-10-2008, 05:04 PM
Ahh HR a foil!! thought I could see a white one through the glare but wasn't sure, it's very hard to get honest figures with one of them fitted, consider taking it off and raising the engine a hole (or not) and re-test.

It almost doesn't matter what planing hull a foil is put onto if the hull has been set up to work at best efficiently adding a foil will ruin it every time.

Are your speed numbers GPS?

cheers fnq

Hornet Rider
05-10-2008, 05:35 PM
fnq, thanks mate, yes they are GPS speeds. I'll bin the foil, take it up a notch & retest I think. With the foil on I noticed yesterday hanging over the transom as my son worked the trim, the foil at best trim at about 3000 rpm was about 80-100mm below the surface, so that suggests I should be able to get the motor up another notch?

cheers, HR

Chimo
05-10-2008, 05:38 PM
HR

I think your right about going up one more.

The express will throw your passanger and you out before it lets go in a tight turn. Back in the 90s I threw the salesman from his seat to the opposite side of the boat when he insisted I go for a test and give it to it even tho I said I knew what they were like. Hell it was a giggle!::)

You can try it up and see what happens in a straight line and on hard turns. If its good straight and it cavitates on the hard turns you know your at the right height for what you want. You can always drop it back even at the ramp on the trailer with a lump of wood under the skeg and the with jockey wheel for fine tuning.

Re the foil IMHO I dont find them an issue doing what your doing as the foil should be way above the water when your running at speed.

Whens the next chapter?

Cheers
Chimo

PS just read your last post, How far back are you trimming to get your revs up? It doesnt sound like the motors back / trimmed up if the foils that far under the water as it would only be there with the motor trimmed in close to the transom.

FNQCairns
05-10-2008, 05:50 PM
Some numbers that may help, at 5000 rpm speed will be around 47kph at 5500 52kph, at 6000rpm 57kph, this is with 12% slip and any 17p prop. Is your speed from a a paddlewheel or was the rpm reading not very precise?

If you can get the wot to 5700-6000 you can be near assured that the full 70hp is reaching the water atm you might only be producing 60.


cheers fnq

FNQCairns
05-10-2008, 05:53 PM
Oops there was a big gap between starting to reply and actually posting so I completely missed the posts above. yeah I would agree go up one more and take the foil off, you can always put it back on when you get it sorted, the drag they produce at cruising speed and below can make them costly to own.

cheers fnq

Hornet Rider
05-10-2008, 07:59 PM
Chimo, 'The express will throw your passanger and you out before it lets go in a tight turn' - ah so that's what the full harness seat belts are for. I thought they were for keeping you in the boat on a big hook up :o I remember you telling me about the sales guy doing the pin ball tango. The express does stick like glue, we've throw it around before just to see what it can do.

As for the foil trim, it was trimmed out enough at 3000 rpm to keep the hull on the plane. Maybe my Mk1 eye ball needs recalibrating, but the distance from the top flat part of the foil to the water was about two flat hands width, say about 80 cm or so? Apart from the WOT of only 5300, I was thinking the best indicator for being able to raise the motor another notch was the fact that the foil was still 80 cm or so below the water line, if that makes sense? Next chapter is next weekend, hopefully. Out with the engine lifter. Too much hassle doing it on the ramp. Have to move both batteries to get at the bottom two engine bolts from inside the transom.

fnq, the tacho is a systems check one & came off a 2008 model e-tec set up off ebay for $70 when the guy replaced all the analogue guages with digital. It has two rpm settings on the back, either 5 or 6, & I've got it set to 6. Cross checked it's reading with another OMC gauage without systems check & they both gave compatable readings. Paddle wheel on the lowrance 525 has always read a bit higher than the GPS speed reading so I note the paddle wheel reading but work off the GPS reading, which I set kts. When I did the 29 kts to kph convesion I just multiplied by 2 & subtracted 10%, but if you use kts x 1.852 then it gives you 53.708 kph instead of 52kph. If the base line accuracy is the GPS, then maybe the tacho is a touch out, ie a couple of hundred rpm short at 5300?

I'll take it up another notch & let you know the outcome.:o

cheers, HR

FNQCairns
05-10-2008, 08:36 PM
Chimo, 'The express will throw your passanger and you out before it lets go in a tight turn' - ah so that's what the full harness seat belts are for. I thought they were for keeping you in the boat on a big hook up :o I remember you telling me about the sales guy doing the pin ball tango. The express does stick like glue, we've throw it around before just to see what it can do.

As for the foil trim, it was trimmed out enough at 3000 rpm to keep the hull on the plane. Maybe my Mk1 eye ball needs recalibrating, but the distance from the top flat part of the foil to the water was about two flat hands width, say about 80 cm or so? Apart from the WOT of only 5300, I was thinking the best indicator for being able to raise the motor another notch was the fact that the foil was still 80 cm or so below the water line, if that makes sense? Next chapter is next weekend, hopefully. Out with the engine lifter. Too much hassle doing it on the ramp. Have to move both batteries to get at the bottom two engine bolts from inside the transom.

fnq, the tacho is a systems check one & came off a 2008 model e-tec set up off ebay for $70 when the guy replaced all the analogue guages with digital. It has two rpm settings on the back, either 5 or 6, & I've got it set to 6. Cross checked it's reading with another OMC gauage without systems check & they both gave compatable readings. Paddle wheel on the lowrance 525 has always read a bit higher than the GPS speed reading so I note the paddle wheel reading but work off the GPS reading, which I set kts. When I did the 29 kts to kph convesion I just multiplied by 2 & subtracted 10%, but if you use kts x 1.852 then it gives you 53.708 kph instead of 52kph. If the base line accuracy is the GPS, then maybe the tacho is a touch out, ie a couple of hundred rpm short at 5300?

I'll take it up another notch & let you know the outcome.:o

cheers, HR

Yeah I always trust the GPS but nothing else until proven otherwise at least, at wot with those numbers you have 5% slip at the moment, 5% is not possible at the sped you are travelling at esp with a foil fitted.

You may have the answer re the poles, although I cannot remember what a 70 should be, some of the 2 cyl omc's were number 4 setting, the v4 s were 6...it sort of puts your 70/3 within the possibility of a number 5 setting??? Hope someone knows for sure as it may right your numbers.

Cheers fnq

Hornet Rider
05-10-2008, 11:43 PM
Yeah I always trust the GPS but nothing else until proven otherwise at least, at wot with those numbers you have 5% slip at the moment, 5% is not possible at the sped you are travelling at esp with a foil fitted.

You may have the answer re the poles, although I cannot remember what a 70 should be, some of the 2 cyl omc's were number 4 setting, the v4 s were 6...it sort of puts your 70/3 within the possibility of a number 5 setting??? Hope someone knows for sure as it may right your numbers.

Cheers fnq

fnq, apparently 70/3 omc motors have a 12 pole alternator so the setting is 6.

cheers, HR

Hornet Rider
18-10-2008, 09:19 PM
More test results from today in the Brissy river to Mud & back. Reasonably flat conditions on the way out, tad bumpy on the way back until just inside the river mouth. Took the foil off & was 85 kg lighter today, with only 2 up. Noticeable difference without the foil. At best trim at each rpm setting got the following:

3000 rpm: 18 kph
4000 rpm: 36 kph
5000 rpm: 48 kph
5500 rpm: 53-54 kph
5600 rpm: 54-55 kph
5700 rpm: 55 kph

Hung over the transom to view the cav plate at each best trim setting. The cav plate was about an inch under the surface each time. If I go one more hole up, that will lift the motor about 1.5 inches, & probably expose the cav plate at best trim. The steering cable will be a problem if I raise the motor. It runs under the rear sbd seat & lifting the motor will require a seat modification. Not keen on that.

Better fuel economy today. Repeated the test as close as possible to last week, about the same distance & rev ranges & used 8 ltrs less. Comes out of the hole like a rocket, but doesn't hold the plane as well between 2000-3000 rpm as with the foil.

Might put the foil back on & see if I can borrow some props for fine tuning. Still didn't get WOT of 6000 rpm.

cheers, HR

FNQCairns
19-10-2008, 11:04 AM
Hi mate thats looking better IMO, good set of numbers!, slip is a little lower than 12% on average, have yet to run the numbers but will get to it, this will show just how much room to move you have to put the foil back on. Foils ruin everything, Could wedges instead help? It's all about give and take.

Based only on a glance at the numbers above and what you have said, if you fit a foil then 17p will probably be too much pitch, you will need to go down to a 15 or 16. ATM you are borderline and that's without the foil.

Possibly a vengeance 13 1/8x16 SS?

Still you could try that SS 13.25x17, it being ss will not automaticly give you what you want, less cup or pitch or surface needs to be designed into it as well...so it's worth a test but not an outright purchase until you have the numbers from it.

Does OMC/BOMB make a 13x17p these days? If you would like to keep near the speed at cruise you have now the only place you can go is down in diameter as the prop you own is a fairly low surface area to pitch prop already.

Another choice would be to get some of the cup taken out of the prop you have to decrease turning resistance and/or get it tipped, you may find 200rpm, just need to trust the bloke doing it that you get something good back.

cheers fnq

Hornet Rider
26-10-2008, 08:35 AM
Hi mate thats looking better IMO, good set of numbers!, slip is a little lower than 12% on average, have yet to run the numbers but will get to it, this will show just how much room to move you have to put the foil back on. Foils ruin everything, Could wedges instead help? It's all about give and take.

Based only on a glance at the numbers above and what you have said, if you fit a foil then 17p will probably be too much pitch, you will need to go down to a 15 or 16. ATM you are borderline and that's without the foil.

Possibly a vengeance 13 1/8x16 SS?

Still you could try that SS 13.25x17, it being ss will not automaticly give you what you want, less cup or pitch or surface needs to be designed into it as well...so it's worth a test but not an outright purchase until you have the numbers from it.

Does OMC/BOMB make a 13x17p these days? If you would like to keep near the speed at cruise you have now the only place you can go is down in diameter as the prop you own is a fairly low surface area to pitch prop already.

Another choice would be to get some of the cup taken out of the prop you have to decrease turning resistance and/or get it tipped, you may find 200rpm, just need to trust the bloke doing it that you get something good back.

cheers fnq


fnq, apologies for late reply, been busy elsewhere. Have decided to take it up the last notch & leave the foil off to see what happens. Will then be able to say I've explored all the options on height. Can't find anywhere that OMC/BDR make a 13x17P Will see what the next round of testing reveals.

cheers, HR

Chimo
26-10-2008, 09:21 AM
HR

Take the foil with you and after trying with it off you can always slap it on while your in the water. With the motor up the next hole the foil should be above the surface when your running with the motor trimmed out anyhow. The foil's only going to contribute to bum lift at slow speed when you want to plane slower anyhow.

Enjoy the F111s today before your namesake takes over for whats left of the "Indy" or what ever they are going to call it after the indy cars bail which is probably next weeks news.

Cheers
Chimo

FNQCairns
27-10-2008, 03:18 PM
fnq, apologies for late reply, been busy elsewhere. Have decided to take it up the last notch & leave the foil off to see what happens. Will then be able to say I've explored all the options on height. Can't find anywhere that OMC/BDR make a 13x17P Will see what the next round of testing reveals.

cheers, HR


Sorry missed you last post HR, IMO if you leave the foil off you can then work toward the most efficient end result, once you reach it you can choose to put it back on and ruin the numbers ie up to a pitch less needed to perform again but never like it did with the pitch it lost to accommodate the foil. They are great for slow planing but become a measurable liability everywhere else. The plate aluminium ones are the best compromise.

Was talking to bloke Via PM a little while ago, from memory by just the removal of the fin he gained 11% in top speed, that may easily equate to 7% or more higher speed fast cruise at the old rpms...that's effectively a straight up 7% or more discount at the fuel bowser, no small chunk of change over a year of boating + the extra user friendliness of driving a boat that behaves as if it has found new HP.

Hope it works for you, every test needs to be in most typical (heavyest) offshore/fishing trim otherwise the assumptions needed each new set of numbers becomes confusing.



cheers fnq

Hornet Rider
04-12-2008, 05:44 PM
Sorry missed you last post HR, IMO if you leave the foil off you can then work toward the most efficient end result, once you reach it you can choose to put it back on and ruin the numbers ie up to a pitch less needed to perform again but never like it did with the pitch it lost to accommodate the foil. They are great for slow planing but become a measurable liability everywhere else. The plate aluminium ones are the best compromise.

Was talking to bloke Via PM a little while ago, from memory by just the removal of the fin he gained 11% in top speed, that may easily equate to 7% or more higher speed fast cruise at the old rpms...that's effectively a straight up 7% or more discount at the fuel bowser, no small chunk of change over a year of boating + the extra user friendliness of driving a boat that behaves as if it has found new HP.

Hope it works for you, every test needs to be in most typical (heavyest) offshore/fishing trim otherwise the assumptions needed each new set of numbers becomes confusing.



cheers fnq

FNQ, finally got the time raise the 70 the last notch. Put the foil back on & tested it on sunday last. What a difference a few cm make. With 2 up, full fuel, & all fishing gear finally got WOT at 6000 rpm with top speed of 55.4kph on the GPS. Can feel some slip in there. Probably would get a more top speed without the foil, but at best trim angle on the plane at any speed the foil is out of the water & not inducing drag. With dual batteries in the stern & with the extra 25 kg of the 70 vice the 50 rude, I think I will leave the foil on. It gets the bum in a flash & on to the plane. 55kph is plenty of go for the Express & it's nice to know it's there if needed. I'm thinking the only thing to counter the slip is go for a quality 13.25x17P in stainless. Could be something I might ask santa for.

Appreciate the advice from you & Chimo along the way on this project.

cheers, HR

PS Had to jiggle the steering cable a bit after I lifted 70 the last notch, but otherwise no mods need to the aft seat.

FNQCairns
04-12-2008, 09:40 PM
HR it all sounds really good!, your pulling good and healthy RPMs for long engine life and 55kph is fast enough with a good and easy 42kph to cruise at all day long at that weight, the extra couple of kph you 'might' be able to get may not have been there anyway. Actually if as you say the foil is free of the water now it wouldn't be impacting anyway.

Never ceases to amaze the before and after results when taking the time and bother to gain a basically ok setup, turns a knackery nag into a brumby at times.

I forget offhand what prop you have on it but don't automatically assume the SS equivalent will be give better gains yet again, it might but it may not, IMO test it before buying it.

Good luck.

cheers fnq

Hornet Rider
04-12-2008, 09:48 PM
HR it all sounds really good!, your pulling good and healthy RPMs for long engine life and 55kph is fast enough with a good and easy 42kph to cruise at all day long at that weight, the extra couple of kph you 'might' be able to get may not have been there anyway. Actually if as you say the foil is free of the water now it wouldn't be impacting anyway.

Never ceases to amaze the before and after results when taking the time and bother to gain a basically ok setup, turns a knackery nag into a brumby at times.

I forget offhand what prop you have on it but don't automatically assume the SS equivalent will be give better gains yet again, it might but it may not, IMO test it before buying it.

Good luck.

cheers fnq

FNQ, yes I'm a fan of try before you buy. Might be able to borrow one of those flash s/s jobs. Will let you know if there's anything more to this journey.

cheers, HR

Chimo
05-12-2008, 06:49 AM
HR

Good result and obviously worth going the extra step which you did and many don't. Still those who don't have always got something to complain about.

I agree with FNQ about trying before buying and would add that in the meantime cleaning up any nicks etc on the current prop could make a differnce to slip and top end performance too. As you say Xmas is nearly here too.

Cheers
Chimo

PS Was good to catch up the other day too.