yamaha 4str 60 overheating problem

[Scott nthQld]

Well with the awesome weather we had this weekend, i chose to head out Sunday morning at 4 am. The boat hadn't been wet in a while so all the pre chrecks were done, battery charged, give motor a run, everything was onboard and in working order etc. All was good, till we got about 400m from the ramp at 4am. Temp alaram was going off its head, and I turn around the see STEAM coming from the tell tale, so I crapped my dacks, shut it off and paddled back to the ramp, luckily an incoming tide so that made it easier.

Now about 8 months ealier, i had the opposite trouble ie the motor wasn't getting UP to proper temperature, and I replaced the thermostat, job done, and since then i have put another 30-40 hrs on the clock. This is the first time I have used the boat in about 3 months due to work and other commitments, but always regularly put the muffs on for a few minutes every couple of weeks or so.

Given the previous problem i had with the thermostat, I figured it would be that again and pulled it out, and the amount of crap covering it was astounding, esp after only 8 months, with fresh water flushing after each and every trip. I thought it was surely the problem so cleaned it up back to new and made sure the thermostat could actually open before putting everything back together.

Once everything was put back where it should be, i put the muffs on and fired her up, no problem, idled for about 10 minutes, so i opened the throttle a bit and about 30 seconds in, temp alarm going off. Water coming out the leg was quite hot, so shut it down again.

I have and idea what may be causing the problem, but have no idea how to go about fixing it.

I think it may be the sender unit that tells the thermostat when to open/close, having a look where the thermostat sits, on the left side ther is a brass, looking nut, with some wires going to it, it makes contact with the thermostat inside the chamber, so I'm guessing this is some sort of temp sensor that causes the thermostat to open/close as required.

i figured i could fix it myself, but when trying to undo the brass nut on the outside, the wires running through the centre of it, twist up and get tighter and tighter, eventually stopping me from undoing the nut any further.

does anyone have any suggestions on how I would go about getting this fixed? I am told that it is a common problem (well thermostat anyway) with my model so would like to be able to do it myself if it's going to be a regular thing, rather than paying someone some stupidly exorbitant fee to do the same job.

[FNQCairns]

First pull the thermostat again and immerse it in a pot of NOT boiling water and bring the temperature up but never to boiling for an outboard engine thermo, best if you can measure the crack temperature and the fully open temperature when you do it although no mandatory also take note of how far it does pull open.

Thermostats do often fail, no rhyme or rythem to it but urban legend has it that often an overheated engine will ruin a thermostat......funny because that's putting the cart before the horse.

cheers fnq

[Noelm]

OK, the cooling system is a pretty simple thing, there is only three things that cause an overheat, no water being pumped, no water flowing after it is pumped, or a false alarm (which is not an over heat) Yamahas have notoriously small water passages, and block up quite often, remove the thermostat (as FNQ mentions) and test it to make sure it is opening, if it is, then you may need to look into pulling off some covers and head to clean out the water passages, but do the easy stuff first. If the water pump was replaced recently, was any of the impeller missing? also very common for a small bit to lodge somewhere and cause the problem later on.

[Noelm]

OH, I forgot, thermostats are not "told" to open, they open from heat from the water, thats why you can test it by putting it in boiling water!

[Scott nthQld]

well here the verdict:

'New' thermostat put in 8 months ago...rooted, put it in a pot with cold water, on the stove to bring it up to temp......water BOILED and still didn't open


I then figured stuff it, let's run the motor for a bit without the thermostat, off she goes, about 3 min in the tell tale was HOT, enough to burn myself....not cool.

Leg is coming off tomorrow to check the impeller, if thats all good, I dunno what then, how am I supposed to clean out any blockages in the cooling system without having to strip the motor down?

If that doens't work I think I'll just make sure the insurance is up to date, take it out, hot or not and undo the bolts and create a new artifical reef. It's bullshit, regularly serviced motor running like a dream until thermostat problems last year, now just problem after problem.....won't be buyng yamaha again if I don't soon sort this peice of shit out

[Dan5]

My old 2000 model 7o suzie used to get bad calcium build up in it after a few hundred hrs of trolling in the fresh,

Every now and then i took of the thermostat cover and filled it up with Barrs radiator treatment.....it would loosen up the calcium and shite that was in there.....Also i've been told by some other that CLR clear does a good job at loosening up that white crud.

Give it a go for $25 it can't hurt.

Dan

[Spaniard_King]

Put a 60 Degree Honda Thermostat in it:-X .. works for me;D

[dreemon]

If you pull the leg off and the impeller isn't rs and seems ok, prob best to change it anyway, re check it and if it's still getting hot " too hot is when you cant hold your hand on the head for close to 10 seconds while running"

then most likely is your water passages getting blocked with the same crap you found on your thermastat, it's not really that hard to clean out just takes time to do it, when I did mine ( yam 90) I found heaps of amazing stuff clogging got about 2 cups of crud ! I could barely believe water was able to get through,

pull the side cover off being really carefull when loosening the bolts in order " there all numbered" work them out very slowly, same with the head, theres 2 plates to remove on each, and you'll need 4 new gaskets,

HOLY CRAP, I just saw this is a 4 stroke ! ! ! is it similar at all to 2stroke?

maybe get a mobile mechanic to remove you clean and get the parts and have him re assemble ? ? anyway . good luck,

[Spaniard_King]

HOLY CRAP, I just saw this is a 4 stroke ! ! ! is it similar at all to 2stroke?
,


yep.. only a few extra bits to fiddle with like timing belt, tappets ,inlet manifold, oil pump etc.. Plenty to do before dissasembling the engine.

[myusernam]

well here the verdict:

'New' thermostat put in 8 months ago...rooted, put it in a pot with cold water, on the stove to bring it up to temp......water BOILED and still didn't open


I then figured stuff it, let's run the motor for a bit without the thermostat, off she goes, about 3 min in the tell tale was HOT, enough to burn myself....not cool.

Leg is coming off tomorrow to check the impeller, if thats all good, I dunno what then, how am I supposed to clean out any blockages in the cooling system without having to strip the motor down?

If that doens't work I think I'll just make sure the insurance is up to date, take it out, hot or not and undo the bolts and create a new artifical reef. It's bullshit, regularly serviced motor running like a dream until thermostat problems last year, now just problem after problem.....won't be buyng yamaha again if I don't soon sort this peice of shit out


If not the impeller maybee compressed air and give it a good blow? maybee some CLR or some calcium eating draino or something in the thermostat hole (might eat impeller). or at also if you are servicing yourself there might be anodes in the water passage that you're not changing that are blocking/ depositing stuff?

Nothing beats experience and I bet if you took it to rising sun they would be able to diagnose it very quickly. Just ask them for a quote to repair and ok two hours labour. I bet they fix it in one.

No matter what you think of them, the local yamaha dealer is the best person to ask for any sort of obscure problem IMHO. Mechanics will say that all engines are the same etc but not when it comes to model specific quirks or problems. Also the manufacturer would release service bulletins etc and also have a specialist that they can ask if they're stumped. Im a genuine service agent (not for outboards) and the things you learn working on the same brand of thing repeatedly is quite surprising.

[black runner]

After checking the water pump, run some Salt Away through the system. There is a salt buildup removal procedure apart from the normal flush.

I have been trialling it and will pull the stat on the weekend to see if it has made a difference in the stat area.

One of my work mates had the same problem as yours with a Suzuki some years ago just before going on holidays. After replacing pump/stats he still had a buildup and bugger all pee stream but couldn't get it looked at in time so he gave Salt Away a try and after a couple or three flushes he was in business.

Worth a go I reckon. Is the motor running smoothly?

Cheers

[Scott nthQld]

yeah, motor is running fine, just getting very hot, I normally flush it on the muffs, but to check the impeller was pumping fine, I did it in a cut down wheelie bin yesterday. Teltale is not as strong as normal though, so it could be one of 2 things, that I should be able to rectify, either the impeller, which I will find out this arvo, or a blockage, I'm hoping its the former.

If not I'll get some salt away and try that first, I've heard good things about it, I'll removes the thermostat cover and spray it in with one of those weed kill pump thingoes and see if that makes any difference.

I would take it into Rising Sun Marine, but to be honest, i'd much rather keep both my arms and legs, one of each just won't cut it, after what they charge. I use an ex-employee of theirs, a certified yamaha mechanic and service agent, and he charges less than half what they do and he comes to me.

I'll try the salt away and might as well put a new impeller in while I have the leg off and see what happens, can't hurt.

[myusernam]

yeah, motor is running fine, just getting very hot, I normally flush it on the muffs, but to check the impeller was pumping fine, I did it in a cut down wheelie bin yesterday. Teltale is not as strong as normal though, so it could be one of 2 things, that I should be able to rectify, either the impeller, which I will find out this arvo, or a blockage, I'm hoping its the former.

If not I'll get some salt away and try that first, I've heard good things about it, I'll removes the thermostat cover and spray it in with one of those weed kill pump thingoes and see if that makes any difference.

I would take it into Rising Sun Marine, but to be honest, i'd much rather keep both my arms and legs, one of each just won't cut it, after what they charge. I use an ex-employee of theirs, a certified yamaha mechanic and service agent, and he charges less than half what they do and he comes to me.

I'll try the salt away and might as well put a new impeller in while I have the leg off and see what happens, can't hurt.

Hear what your aying about rising sun! hey if that ex employee you're talking about wants some more work can you pm me his details? I have a yammie on my liitle boat. thanks

[FNQCairns]

Consider too that some engines in the past do not take kindly to running on muffs without a thermo fitted, they will exhibit overheat in this senario but may not on the water.

Also I understand but am happy to be corrected that modern 4 strokes run hot compared to equivalent traditional 2 strokes, because all of the nasties that clogs gallerys are formed directly as a consequence of heat and the hotter (even 10deg) it runs the more depots created over the same time frame, it's expected of 4 strokes to get gummed up early compared to what was historically typical.

I do not know anything of that engine but it sounds like doing the pump is a worthy idea although a stronger pump might only cover up the constriction if you have one and then with an engine running another 7 deg over normal (also hot spots) but not actually at overheat it's a catch 22 not to mention the extra work because of temperature the oil has to do etc.

Your choice obviously but if it where me first I would fit a new thermostat and try again. Irrespective of the outcome you will be in a better place to choose options and the cost to get there was no greater.

cheers fnq

[black runner]

If you are going to use Salt Away, also get the metering attachment. Remove the thermostat, temporarily reinstall the stat gasket and cover and use the motor's garden hose attachment. Leave the hose on normal flush for at least 15 mins and then introduce Salt Away using the inbuilt tap. Repeat after several hours as per the instructions. Don't forget to reinstall a new stat.

I also flush mine religiously after every trip but still got a build up of salt in the stat area. Will let you know the results with pics on the weekend

Cheers

[myusernam]

hey scottnthqld did you work out what was wrong?

[Scott nthQld]

nah not yet, can't get the friggin leg off, I'm sure I've undone all the bolts, it just won't friggin budge

[neil_stessco]

How many have you undone? it should come off easy enough.

[Scott nthQld]

I've undone the 4 around the the underside of the fin above the cav plate, as well as the one that goes down through to an anode, can't find anymore, so am lost, i once found an online serivce manual for my motor on the net before, Just have to remember what address it was....should've bookmarked the page when I first found it

[FNQCairns]

Scott try boats.net and look for a schematic of the area.

[sjp2]

Scott stop stuffing around and take it to the mechanic ,ask for a quote before hand maybe ,but at least after they fix it!! you can go back and whinge if it still overheats ,theres some things that cant be fixed without the help of a computer these days.

[Steeler]

Scott

Have you been putting a nickel anti seize on the splines of the drive shaft ?.

Steeler

[Scott nthQld]

Steeler, I have no Idea, the mechanic was the last one to have the leg off.

sjp, don't tell me to stop stuffing around, if you don't want to know about it, don't f'n read about it, you might be made of money, but I'm certainly not, so before I go stuffing around with mechanics draining my bank account, I'm having a go myself

[brisbane_boy]

If the leg is truly stuck your in a world of hurt, it has happened before they can siezed solid, unlikely thou if the last one to pull it off greased it.

[FNQCairns]

Roughly to ascertain if it is the spline or a bolt they way to tell is by how far it has dropped already, if there is a slight or minimal gap it will be a bolt if it is larger and you can wobble it left right some but no much it will be the spline as there is some freeplay vertically can be forced to show in the shaft by just the weight of the leg hanging from it.

[myusernam]

gear linkage under the cowl?

[BoulldogsBoy]

Hi,
I just spoke with a dealer about the type of issue you are having as I am looking at a Yammy 40HP 4 Stroke.

He informed me not to use muffs for a start and to use the hose connection to flush and not to run the motor while flushing. Apparently the system has been designed for this process.

The hose connection is on the left side as viewed from the boat and is simply a matter of unscrewing the comnnection and attaching your hose.

He also suggested to really look after cleaning the trim/tilt mechanism as this is a major cost to replace if neglected.

He did not recommend the Salt Away or CLR.

Being a novice I would say read the manual from cover to cover a few times. IMHO most people toss them in a draw and then blame everyone bar themselves when things do not appear to go as planned.

[Scott nthQld]

Hi,
I just spoke with a dealer about the type of issue you are having as I am looking at a Yammy 40HP 4 Stroke.

He informed me not to use muffs for a start and to use the hose connection to flush and not to run the motor while flushing. Apparently the system has been designed for this process.

The hose connection is on the left side as viewed from the boat and is simply a matter of unscrewing the comnnection and attaching your hose.

He also suggested to really look after cleaning the trim/tilt mechanism as this is a major cost to replace if neglected.

He did not recommend the Salt Away or CLR.

Being a novice I would say read the manual from cover to cover a few times. IMHO most people toss them in a draw and then blame everyone bar themselves when things do not appear to go as planned.

m,ate don't believe a word the dealer says, I use both methods to flush my motor, muffs and the built in hose attachment, for a system that was 'designed' to be flush with the hose attachment only, it doesn't work very well. And of course he wouldn't recommend salt away, the more often you have to take your engine in for servicing and extra maintenance, the more money he makes. Salt away is not a detergent, non corrosive substance and will NOT cause damage to your motor.

Anyway, I found after much diffuculty and some help by another member via pm, I missed a friggin bolt hidden underneath the annode above the prop, once that was out the leg almost just fell off. I won't mention the member who helped as he contact me via pm, so I'm assuming he'd like to keep it quiet, but he was a great help and I think him very much.

I pulled the impeller housing apart, and found more grit and build up inside the housing, impeller was intact but a bit worn, so will be replacing that as well. Looks like my only option for my DIY adventure is give the system a good flush with salt away, and put in a new impeller and thermostat, then see how it goes, if the problem persists, then I'll call my mechanic, at least I will then know I've done everything I feel comfortable doing myself.

[levinge]

Then trade the bloody thing in and get a Honda hey Scott!!!!

Sorry to see you kept off the water on such a beautiful weekend...Should've given me a call, we had room on Monday and went to Grub....

Hope all is fixed soon matey...

[black runner]

Hey Scott, as promised here are some photos of the housing and stat removed after using Salt Away. As you can see, the cooling passage is fairly small so is easily affected by salt build-up.

When I took it apart this weekend (for the first time after using salt away for this season and half of the last) there were minimal deposits which were soft and wiped off, not bonded to any surface. This was very different to last time where the deposits had to be dissolved and scrubbed/scraped from the surface. The thermostat looks like new.

The water passage surface condition that you can see inside was as it was from the clean out last time. This was done as part of a dealer service (who I might add left crap everywhere in the bottom cowl – but that’s another story) whose work I decided to check after the engine check indicator kept coming on due to low water temp – the thermostat was stuffed and stuck partly open.

We are talking 15 months and 40 hours use exclusively in salt water. So it looks like it is working as claimed.

I bought the boat used in October 2006 with 20 hours on and flushed with fresh religiously for 15 mins after every trip and the salt still built up in this area.

Would welcome comment from those who have seen the inside of more outboards than me.

[finlayson]

have you tried running the engine in a bucket of water with the thermostat and cover removed to see weather water is being pumped up to the top of the head? There should be a nice flow of water coming out of there.
How strong is the tell tail? yammies normally have a strong tell tail stream
Yammies have a small water pick up area and with out forcefully holding the muff of the gear box to acquire a good seal it will over heat every time.

Have you removed the water pick up screens and checked for obstructions and blockages there?
You have replaced the water pump impeller yes? and you say the housing was in good condition yes?

What was the water tube grommet like on the pump...these can become restricted but salt build up on the outside of the grommet causing a flow restriction...
If you all is in order there well then the last place the issue might be is under the power head....possible a swollen water tube grommet or a blocked or restricted gallery.

What makes this hard is that with out seeing it and seeing the parts and what the engine is doing it is had to diagnose it...you really should take it to a mechanic. as for those pics all looks normal there except the t stat not working which you replaced yes?
make sure that when you test it you either get a good seal with the muffs and i mean GOOD or use a bucket of water or back her down the boat ramp because you might find that the t stat was the issue and you might of been chasing your tail...because a faulty t stat will case it.
let me know how you go

[black runner]

Here's my take on the issue:

4 stroke cooling passages are more complex and in some places much smaller (especially in the cylinder head) than in an equivalent 2 stroke. Consequently thorough/lengthy flushing of the motor is critical to prevent buildup occuring from one use to the next. This can be difficult in areas where water restrictions are in place especially if required to run the motor and hose for 15+ mins.

Auto and some inboard applications use freshwater/anti-freeze/corrosion inhibitor in a closed circuit cooling system and this pretty well ensures a "clean system".

A continually drained saltwater system exposed to heat and air will leave, and continue to build, salt deposits unless adequately flushed. Smaller 4 strokes due to smaller and more complex cooling passages are less tollerant of inadeqate flushing.

After pulling the thermostat a few times in my 60 4 stroke I am more convinced than ever that a flush additive/residual corrosion inhibitor makes sense. All auto motors run coolant additives to prevent corrosion, why not 'clean' the outboard cooling system in a similar way?

There are cooling passage where the head/block meet that are far smaller than the stat passage and I am sure there are some out there that are almost closed.

I would also advocate flushing the motor using the hose flushing port (motor not running) with the thermostat removed (cover reinstalled) once or twice a season. This will ensure unrestricted flow of water/flush additive through the powerhead. The bleed ports in the stat valve are too small to allow any decent flush flow behind the stat at the top of the head when cold.

Cheers

[Spaniard_King]

BR,

IMO there is no need to flush the engine for more than 5 mins or for 1 min at the correct engine operating temp.

The modern day 4 stroke has beter designed and coated cooling water passages and is not subjected to the same corrosion and build as the 2 strokes

There should be know reason once the water pump is correctly installed and a known good thermostat should a 60 Yamaha over heat unless there is exhaust gas leak into the cooling water passages. However I have found one engine that did not have the water check nozzle in the tell tale which let the water pressure drop enough to over heat the engine.

[black runner]

Thanks Garry,

In your experience do you find that any/most salt buildup in modern 4 strokes is generally in the thermostat area? It would be comforting to know that the rest of the system is generally ok with regular flushing (as you describe) and not simarly afflicted.

Having reconditioned a few auto/truck motors but no 4 stroke outboards, I would be interested in the general condition of water passages and head gaskets in many of the 4 strokes you have stripped down.

I must confess to a belt and braces approach with my own motor in the absence of any evidence regarding the condition of internal passages other than the thermostat and surrounds.

Cheers - Fred

[myusernam]

BR,

IMO there is no need to flush the engine for more than 5 mins or for 1 min at the correct engine operating temp.

The modern day 4 stroke has beter designed and coated cooling water passages and is not subjected to the same corrosion and build as the 2 strokes

There should be know reason once the water pump is correctly installed and a known good thermostat should a 60 Yamaha over heat unless there is exhaust gas leak into the cooling water passages. However I have found one engine that did not have the water check nozzle in the tell tale which let the water pressure drop enough to over heat the engine.


I've got a yammie 60 and a evenrude 115 both with the hose attachments. Are they better for the engine? I have always been suspicious about muffs hurting the impeller because sometimes they dont fit great, I dont have a lot of water pressure, and I have to hold the muffs together to get suction at the start. sometimes the telltale isn't quite as strong. does this mean it's prematurely wearing the impeller?

If you use the hose attachment does it matter that the engine isn't hot?

[Spaniard_King]

BR,

Salt build up varies with different models and it's hard to put a finger on the actual reasons due to differing methods and elements involved with flushing engines.

IMO the best method of flushing an engine is by runing the engine with fresh water to a point where the thermostats are open (hence proper thermostat operation is critical), as long as the impellor is getting wet it will be lubricated and no wear should be taking place on the impellor.

[Scott nthQld]

I usually do run the engine on the muffs, or tub of water for a good period of time, with the engine well and truly upto temp. Usually while this is happening, i am cleaning out the inside fo the boat, and depending what I have been fishing for, could be 5-15 minutes, once the flush is complete on the muffs, I also run fresh water using the hose attachment once the motor has cooled. I figure using muffs/tub with the enigine running is better because:
1. The thermostat opens and lets water in the whole system
2. The engine being warm, heats the water, and warmer water is better at dissolving salt and deposits than cold.

Anyway, new parts go in this weekend, just have to wait for some gaskets to arrive, then i'll give her a run at home, and if all goes well, give her a water test with a mate in another boat justin

[levinge]

Let me know when you want to test her, I will be available Saturday through to Thursday throughout the day...

Happy to make sure all goes well....Give me a call

[bugman]

BR,

IMO there is no need to flush the engine for more than 5 mins or for 1 min at the correct engine operating temp.

The modern day 4 stroke has beter designed and coated cooling water passages and is not subjected to the same corrosion and build as the 2 strokes

There should be know reason once the water pump is correctly installed and a known good thermostat should a 60 Yamaha over heat unless there is exhaust gas leak into the cooling water passages. However I have found one engine that did not have the water check nozzle in the tell tale which let the water pressure drop enough to over heat the engine.


uuummmmm who was that:oops:

[black runner]

I usually do run the engine on the muffs, or tub of water for a good period of time, with the engine well and truly upto temp. Usually while this is happening, i am cleaning out the inside fo the boat, and depending what I have been fishing for, could be 5-15 minutes, once the flush is complete on the muffs, I also run fresh water using the hose attachment once the motor has cooled. I figure using muffs/tub with the enigine running is better because:
1. The thermostat opens and lets water in the whole system
2. The engine being warm, heats the water, and warmer water is better at dissolving salt and deposits than cold.

Anyway, new parts go in this weekend, just have to wait for some gaskets to arrive, then i'll give her a run at home, and if all goes well, give her a water test with a mate in another boat justin

Hey Scott,

What was the outcome?