Evinrude MAJOR Vibration- HELP!

[West Coast Pom]

Evening guys (and girls),

Just took out my newly serviced 70Hp Evinrude 2 stroke (1989) on the water today- first time out since having a major 100hr service.

Anyway all went well, started frist time, pottered downstream at 8knots for an hour, hit the waterski area and opened her up and the problems started:

Got her up to about 22knots, 3000rpm (had her to 30+ before) and after a minute or so, the motor let out an almight cough and stated to vibrate HUGELY!! shut her right down to idel and she then purred like a kitten as if nothing had happened.

So slowly pushed her back up and at about 3000rpm is would start to shake, not a high pitch vibration, but more low frequency, high amplitude "shudder".

Under 3000rpm it's as if nothing happened- even got her back to the boat ramp no bother, nearly an hour away. Of course everytime i tried to give her a nudge, the vibration began again.

I couldnt figure out if the motor was coughing, thus causing the vibration, it felt more like an out and out mechanical shudder i.e. not necessarily FROM the motor, but shaking the motor anyway.

Can't see anything wrong externally, had her over 3000rpm on idle back at home, didnt seem to happen.....could it be the prop? Even though i havent hit anything?

ANY THOUGHTS ANYONE???

[Blackened]

G'day

I'm not sure, but have you had a chat with the mechanic?

How is your prop generally? blades in tact and shaped correctly? bush not worn?

Dave

[West Coast Pom]

Havent had the chance to chat with him as today was the first run sinc ei picked it up and they were closed today!

They are very good reputable mechanics- but i will check on monday

It doenst feel like an "engine" problem i.e. doesnt feel or sound like a misfire- the rpob isn't the best i'll admit but it has been fine for me for months so unless someone has dropped it and bent it maybe?

How do i cehck prob bush? Though the prob was removed as part of the service, so if the bush was gone wouldnt they have noticed during it?

Bloody annoying as the motor runs so sweetly since the service!!

[BM]

Could be a VRO related issue (but I don't think so)

Could be a fuel supply issue (don't think so)

Could be an ignition issue. First place I'd look would be a sticky timer base under the flywheel, then I'd be spark checking each cylinder. Easy to test it on the trailer at a ramp so you can achieve the 3000rpm+ to make the fault occur.

Cheers

[West Coast Pom]

thanks BM,

doubt's it the fuel too, as i re-plumber the whole fule system and had new filters put in last week too. Also fresh fuel and the motor is more than happy up to 3000 rpm, it's just over that the shudder starts

Dunno what you mean by VRO mate- what's that??

How do i check the timer base? Literally remove the flywheel? Is that easy (i have greasy fingers but try to stay away from dismantling my enngines if possible!)

Could it be a dodgy spark plug? As simple as that maybe? What would trigger it off at high revs?

[West Coast Pom]

jeez my spelling is shocking tonight, sorry guys!! haha

[Blackened]

Dunno what you mean by VRO mate- what's that??


G'day

Variable Ratio Oiling (I think thats it, but you get the idea), OMC's automatic oiling system.

Listen to BM on this, he's the guru

Dave

[West Coast Pom]

No worries mate,

I listen to everyone on this, i have only been a boatie for a while!!

The oil injection has been disabled and it's run as 50:1 premix now- if that makes the VRO thingy irellelevant now?

[FNQCairns]

With BM here I suspect a timing issue but would leave it to your mechanic to fiddle with further as there is a chance he is absentmindedly but probably the cause, sounds retarded just when it needs full spark advance (about 1/3 total throttle travel).

cheers fnq

[West Coast Pom]

ok will leave it to the mechanic to sort it out, pain in the *rse as i want to go for a fish on the river tommorrow!

As she runs sweet up to 10knots, you reckon she'd be ok for a bit of a low speed fish in the river- or would you leave it till the mechanic has sorted it out? I suspect i already know the answer to this question though...!

[West Coast Pom]

hey just read something about S.L.O.W (speed limiting overheating warning)- could this also be it?

Only cos someone posted that their motor shook when this kicked in?

If so, why would it kick in when ihave just had the whole water pump assembly replaced? In fact i am getting heaps more water out of the tell tale than every before- so maybe i am misunderstanding something?

NOT saying anyone else is wrong (If i knew the answer i wouldnt be asking, haha!) but like to check out all the options- only way i'll learn!

[FNQCairns]

Displacement speeds should be ok but suspect no one would recommend it as a good idea without a firm diagnosis.
IMO say today it blew up, the chance any mechanic would put his hand up and say they caused it through the service would be drastically slim considering the logical number of other faults/causes they could make stick in the customers mind and to those who don't know outboards...do you get my drift??

cheers fnq

[FNQCairns]

hey just read something about S.L.O.W (speed limiting overheating warning)- could this also be it?

Only cos someone posted that their motor shook when this kicked in?

If so, why would it kick in when ihave just had the whole water pump assembly replaced? In fact i am getting heaps more water out of the tell tale than every before- so maybe i am misunderstanding something?

NOT saying anyone else is wrong (If i knew the answer i wouldnt be asking, haha!) but like to check out all the options- only way i'll learn!

Sounds like you nailed it!!!!! at least it's a great explanation.

cheers fnq

[West Coast Pom]

cheers fnq,

yeah i get your drift mate- i would not expect them to accept any responsibility if it died, so prob best to leave her alone to limit the prospect of a big $$$ bill!!!!

Weird symptom though!! Certainly got me thinking about doing an outbaord mechanics course!!

[Roughasguts]

I'm thinking you got a spark plug fouled up, plenty of idling with a cold motor at 50-1 can do that.

Take them out and give them a clean with Carby clean and a tooth brush or a small wire brush. Think you might find the bottom plug being the problem, being the coldest.

If it isn't the plugs then it might be a bad coil breaking down under load.

Might be easiest to do a simple touch test and check the temps around the spark plugs with the back of your finger after a run to check each cylinders temp.

The whole idea is to hold your finger near the plug and if you can count to 7 seconds the motor is running at a good temp.

But if less the motor is to hot.

If more than 7 seconds 10-12 the plug might not be firing.

Don't worry you won't end up in the burns unit, an outboard motor doesn't get as hot as a cup of coffe with plenty of milk.

[BM]

Did you re-do your fuel system or the mechanic? No offence but people do strange things sometimes.

How many filters are we talking???? and what type?

Cheers

[tigermullet]

I'm thinking you got a spark plug fouled up, plenty of idling with a cold motor at 50-1 can do that.

Take them out and give them a clean with Carby clean and a tooth brush or a small wire brush. Think you might find the bottom plug being the problem, being the coldest.

If it isn't the plugs then it might be a bad coil breaking down under load.

Might be easiest to do a simple touch test and check the temps around the spark plugs with the back of your finger after a run to check each cylinders temp.

The whole idea is to hold your finger near the plug and if you can count to 7 seconds the motor is running at a good temp.

But if less the motor is to hot.

If more than 7 seconds 10-12 the plug might not be firing.

Don't worry you won't end up in the burns unit, an outboard motor doesn't get as hot as a cup of coffe with plenty of milk.


That's a very good idea! Your problem could be as simple as that especially if you have those mongrel resistor type spark plugs fitted.

[marco]

maybe have a check of the fuel lines and filter that you installed , any kinks or restrictions that may cause fuel starvation at the higher rpm ?
it usually pays to check out the simpler things first

sorry bm , didnt see your post about the same thing

[BM]

No worries marco. No need to apologise to me mate!!

[Spaniard_King]

WCP,

when you turn the key to on are you getting 2 beeps of the alarm?

If you arnt I recon you are going into slow due to the over heat circuit trigering.

Another way to chek your over heat alarm is to start the engine on the muffs and seperate the tan wire going to the temp switch (located in the cyl head at the rear of the engine) earth the tan wire from the loom to the block this should set off the alarm. Use a small metal object to help earth the tan wire to the block.

I have had this before on 3 cyl OMC engines.. the water jacket on the port side of the block gets a build up of salt deposits and blocks the very small water passages sending the engine into slow only when high rpm is used.

[Outsider1]

WCP,

your description of the "cough" and then shudder type vibration certainly sounds like it is going into "limp" mode. I can recall it happening to me with a 150hp Johnson V6 a few years ago. It was an overheating problem in my case, if a recall rightly!?, a faulty thermostat I think.

The shudder is quite pronounced, almost like something is shaking the motor, or the prop is caught in something like a net (catching and releasing).

Given you have just had the service down, I would be taking back to the mechanic to check on Monday.

Cheers

Dave

[West Coast Pom]

cheers guys,

well the strangeness continues...couldnt resist taking it for a quick fish today- the weaterh was just TOO perfect (<5knt wind all day and <1.5m swell), anyway IT WAS AS IF NOTHING EVER HAPPENED?!!

Took her out, was very gentle with her cos of yesterdays problems, kept giving it a bit more and more and eventually had it up around 4000rpm and on the plane nocely....weird!!

maybe roughasguts was right with his fouled spark plug and a good burn cleaned it out?

still going to ring the mechanic tommorrow just in case but...!!

cheers guys, will keep you updated!!

p.s. fishing was HOT too, belly full of herring fillets as i type ;o)

[FNQCairns]

Good news! but keep half an eye on it, gremlins have a habit of returning with a thud and sometimes never. With hope it's the later.

cheers fnq

[West Coast Pom]

Hi guys,

Thanks for all your responses, I have a few replies for your info and to give you an update:

BM: I re-plumbed the whole fule system (up to the engine) a while ago and have had no problems with it since but just in case: got three filters- 1) inline, glass, steel gauze solids filter off the internal tank 2) cartridge type fuel/ water filter downstream of the primer bulb (installled the right way, haha) and 3) the little plastic in line one inside the engine cowling (the mechanic replaced this as part of the service. so hopefully fuel starvation isn't the problem- but maybe i am wrong?

Tiger- will pull the plugs out tonight and give them a clean to be sure- good idea!! Just a thought though, why would it only affect it at high revs?

Spaniard- I dont get any beeps when i start the motor, in fact i dont even know if there is an alarm- i have never heard it!! Maybe cos it's a 1989 it doesnt have one or cos it's so old it's cactus? But, checked with the mechanic and the thermostat was replaced as part of the service. If i pull the tan wire out on the muffs and earth it should that cause the S.L.O.W mode to lick in? If that happens then presumably that confirms what happened i.e. that the thermostat (even new) is faulty or the salt build up is happening as you mentioned?

Outsider- yeah you described it EXACTLY- a shudder like the motor is being shaken, but doesnt sound like a misfire- weird innit? So maybe the thermostat is faulty after all? Or it picked up a bit of sh*t that blocked it that one time?

Anyway I called the mechanic today and described it and he confirmed the motor has a S.L.O.W function and it sounded like it had kicked in. He confirmed the new thermostat and full water pump system (not just the impeller) was installed.

i asked him why it wouldnt happen the next day and he didnt' know why it happened internittently, but suggested perhaps it just needed a good run and if SLOW mode kicks in again to bring it back to the shop and he will look at it further. He mentioned that SLOW mode was to protect the engine from overheating (and it is clearly working) and by taking it out for a good spin will confirm it if its happens again but to no detriment to the engine if it kicks in, just take her slow back to the ramp and bring her back to the shop (where they offered to a do a water test). Sound like a good plan to you guys?

Thanks again for your help lads, this place is a lifesaver (or should i say, engine saver!!)

Pom

[Roughasguts]

Which west coast you from West Coast Pom.

S.A's west coast ?
Use to live there a long time ago.
That's where I learn't to be a bush mechanic well maybe not! just Roughasguts.

[West Coast Pom]

haha sorry mate, THE West Coast, Perth!

Great boating over here mate, but tell ya what- bloody arvo seabreezes here are a pain in the *rse!

[Spaniard_King]

WCP,

Get that alarm fixed ASAP, could save you big$$ down the track.

[West Coast Pom]

Yeah been doing plenty of researc on the net today (i am sure i should be working) and will do the alarm test tonight.

SK- you seem to know about this, if i understand right from what i have read the simple test should be: disconnect the tan wire from the switch (not the loom/ harness) and ground it (to the block) and the alarm should sound? Is this the right way around?

Also do i need the engine running for this or just the ignition?

Cheers
WCP

[Spaniard_King]

WCP.

the way it works is the engine has to be running.. The alram circuit is trigured by earthing out the circuit either VRO or overheat.

So with the engine running dissconnect the tan wire from the temp switch and using a mmetal object extension (screw driver) earth the lead.. "not" the switch to the block

[West Coast Pom]

ok so start her up (cover off), pull the tan wire from the temp switch and ground it to the block.

I would be expecting the alarm to sound yeah? If not, the alarm is cactus.

If the alarm does actually sound, that would imply that there is an issue with the temp switch then i.e. it is not sounding the alarm. Does the temp switch also force it into s.l.o.w mode?

It seems to me then that either the alarm is knackered but the temp sitch is fine, i just can't hear the alarm (which may be unlikely as the entire pump assembly is brand new) OR the temp switch is cactus and it's triggering the S.L.O.W mode? would this be a reasonable assumption?

Cheers WCP

p.s. it isn't the VRO, as it has been disabled (pre-mix 2-stroke now)

[Spaniard_King]

WCP,

you are earthing out the wiring loom..............you are not earthing out the switch

To test the switch you have to remove it from the head and heat it in a liquid to the prescribed switching temp then use an ohm meter to check for switching at the right temp.. ususllay just change the switch :P

Just because you are premixing doesnt mean your alarm circuit is inactive... find the VRO wiring plug and ensure it is disconnected and the loom end of the plug is filled with grease.. otherwise iof corrosion sets in the plug it could also set the engine into SLOW thru a short circuit in the VRO plug.

[West Coast Pom]

Cheers Gary

Sweet- will test the alarm tonight

If it's not the alarm will test the temp switch

If it's not that will find the VRO wiring plug, ensure it's disconnected and fil the loom end with grease!

What could be easier- haha!!

WCP

p.s. also just read that the power pack can "stick" in slow mode and can only be-reset by turning off the engine and restarting. This would explain a lot as i didn't shut it down the first time round and it kept doing it at 3000rpm. Of course, the next day it was restarted and all worked fine! So i am fairly convinced it's the SLOW mode thingy- just gotta find the cause now!

Thanks for your help!

[Spaniard_King]

yep, that is true with your engine. to reset from SLOW the condition must be rectified AND ignition turned off and restarted.. good luck :)

[West Coast Pom]

thanks heaps Garry

will let you know how i get on!

James

[cormorant]

Same symptoms can be a worn or out of adjustment clutch dog. Moved andy control cables when rerouting the fuel . Possibly check gearbox oil for metal shavings.

A damaged high tension lead can also be a chance. Many get damaged by mechanics at service as they are ripped off plugs by the lead rather than the boot and boots aren't greased before replacing. Cowls also get jammed on them so have a close look for any damage to them.

Coil - as mentioned - a chance

Thermostat in backwards or seized

Possibility 5% of it being fuel pump diaphram - is it idling normally??

Under cowl filter put on backwards?

I don't think the glass filter is needed on your line as one should be enough. If you want to prove it is not a issue with fuel just usea 2nd tank without any line filters as a quick test and see it it runns normally. Has the right inside diameter pipe been used , fuel bulb in right direction. Fresh filter used as some old stockers that have been exposed to water swell and stop full flow. Last one - possibly air getting into fuel via a connector will stopa motor revving out.

Hope you find it and it's simple.

Corm

a

[Grahamwj]

Don't know if you found the cause of your vibration yet, but if not, check that the accelerator linkage has not disconnected from one of the three carburetors. Took me 6 weeks last year to get to the bottom of a very similar problem with my 70HP Evinrude. My very experienced mechanic could not find it. Engine would run beautifully from idle up to about 3000 RPM, and then it would start to shudder from side to side, and maximum RPM was limited to about 4300 instead or 5500. It turned out the linkage had fallen off the bottom carby, so only two cylinders were getting power when I opened her up. Simple job to fix. Pretty sure my mechanic knocked the linkage off during a service, but he wouldn't have it of course!