Yamaha 60hp 2stroke overheat at idle

[bizzyb]

Hey there 

We have a 1999 Yamaha 60hp 2 stroke that sets off the alarm at idle. I can only imagine this is the overheating alarm as it's using the oil no problem. 

Some research on forums mentioned thermostat, poppet valve and impeller. We've just pulled out the thermostat, a lot of gunk in there but when chucked in hot water it opened. I'm going to replace it anyway given the corrosion and I wasn't able to test if it was opening at 50deg. 

 

I went hunting for the poppet valve but after much searching and a bit of research on workshop manual etc, perhaps there isn't one on this outboard??

 

Does anyone know if it had a poppet valve and if so where would I find it?

 

Any other recommendations to fix the overheat issue?  I'm hoping the thermostat does the trick.  But I guess it could be a worn impeller if at low speed it's not pushing enough water through. 

 

Oh, btw, no problem with the tell-tale, tho I heard that this isn't much of an indicator..

[rickmarlin62]

if the impellor was completely shot you wouldn't have telltale..hopefully thermo is the fix...rick

[Nolongeramember]

So it only happens at idle? I’m going with a worn impellor/ pump. 

When was it last serviced? 

[Nolongeramember]

Also, from cold does it set off the alarm straight up at idle or does it seem to warm up first then the alarm goes off at idle?

[Nolongeramember]

Could also be a build up of salt inside the engine where the water flows through. Only way to fix it is to take the engine apart and physically clean it out. Start with the basics, thermostat and pump then go from there. 

[jeffb5.8]

Clean the water galleries as best as possible, using pipe cleaners, wire and fill with water and blow out with compressed air.

i would change the thermostat and water pump as it may be failing at low speed and not having enough pressure to make it pass any small blockages.

P.S

i am assuming this is when it's in the water and not on ear muffs as some motors don't like to idle for long periods on ear muffs.

Edited October 11, 2017 by jeffb5.8

[bizzyb]

2 hours ago, Hateanchors said:

So it only happens at idle? I’m going with a worn impellor/ pump. 

When was it last serviced? 

Has happened when idling while chasing a hookup and while waiting for the trailer to be backed down the ramp. 

It had 100hrs. Recently purchased. Was told we could go another 50hrs before changing, but that was before we knew about the overheating. 

[bizzyb]

2 hours ago, Hateanchors said:

Also, from cold does it set off the alarm straight up at idle or does it seem to warm up first then the alarm goes off at idle?

No, it has to warm up. 

[bizzyb]

2 hours ago, Hateanchors said:

Could also be a build up of salt inside the engine where the water flows through. Only way to fix it is to take the engine apart and physically clean it out. Start with the basics, thermostat and pump then go from there. 

This was the state of the thermostat. I've given it a good clean out but will do more once the new stat arrives. 

[bizzyb]

1 hour ago, jeffb5.8 said:

Clean the water galleries as best as possible, using pipe cleaners, wire and fill with water and blow out with compressed air.

i would change the thermostat and water pump as it may be failing at low speed and not having enough pressure to make it pass any small blockages.

P.S

i am assuming this is when it's in the water and not on ear muffs as some motors don't like to idle for long periods on ear muffs.

Funny enough the alarm stopped when on the ear muffs.

[jeffb5.8]

46 minutes ago, bizzyb said:

Funny enough the alarm stopped when on the ear muffs.

Then I am backing the water pump is on its way out, the force of the water on ear muffs is compensating for the lack of flow generated by the water pump.

[rickmarlin62]

spot on jeff  the water pressure from hose is pushing water out telltale....change the pump housing and impellor with that much salt buildup showing....you can try a product called saltaway for flushing motor...I havnt seen it for a while but think its still available...rick

[bizzyb]

Thanks everyone. To do list: 

Change thermostat

Change impeller and housing 

Flush with salt away/salt X

Will let you know how it goes.

So, just to confirm, am I right that poppet valve is not a thing on this outboard?

 

[TheFoosh]

No poppet valve but that corrosion is bad. Sort that out and you'll be fine.

[Nolongeramember]

3 hours ago, bizzyb said:

Thanks everyone. To do list: 

Change thermostat

Change impeller and housing 

Flush with salt away/salt X

Will let you know how it goes.

So, just to confirm, am I right that poppet valve is not a thing on this outboard?

 

Don’t bother with Saltaway. It won’t remove the aged, caked on salt residue one bit. I know from first hand experience. 

As I said earlier, the only way is to take the head apart and manually clean it. 

[Peter Nelson]

I've got a yamaha 70hp 2 stroke and when i was flushing the motor the other day the temp alarm went off and i noticed the tell tail had stopped.

Pulled apart and found the impeller shot.

Not sure what happened but i think i might go away from ears and flush from a barrel or large container.

The impeller is easy to change as well.

[TheFoosh]

Ears are the best, they force the crap out under higher pressure. In a barrel all you are doing is recycling the dirty water you just flushed out back through the system again.

[Nolongeramember]

2 hours ago, TheFoosh said:

Ears are the best, they force the crap out under higher pressure. In a barrel all you are doing is recycling the dirty water you just flushed out back through the system again.

Not really. The water pump makes the pressure that goes through the engine. The ear muffs or barrel just get the water to it. 

The amount of contamination from  recycling the water in a barrel is very small and would make no noticeable difference to the cleaning of the engine. 

I actually prefer using a barrel.

 

[bizzyb]

On 12/10/2017 at 1:27 PM, Hateanchors said:

 

As I said earlier, the only way is to take the head apart and manually clean it. 

Any recommendations on where to pick up a cylinder gasket and cover gasket? Or better still, where not to buy?

I don't have a parts # list for this outboard.

[Flickn Mad]

This is the head of my 70 hp yammie.

The motor was overheating at low revs,ie when trolling livies and also at WOT, but not in between.

When I looked at the thermostat it looked a lot like yours.

I always flush the motor on earmuffs but evidently not enough.

The tap water being cold, limited time and being conscious of driving my neigbours made I probably never gave the engine time to get hot enough to open the thermostat for long.

Even after cleaning it up the stat opens very little at idle.

Pressure from the hose is bugger all when you look at the "relief"it gets through the earmuffs, excess pressure just spurts out the sides.

A Drum would allow for the water to warm up, meaning more flow through the t stat.

It would also make a reasonable silencer so you may be happier to run it longer.

If your impeller is missing parts you have wonder where those parts are now?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Flickn Mad]

7 minutes ago, bizzyb said:

Any recommendations on where to pick up a cylinder gasket and cover gasket? Or better still, where not to buy?

I don't have a parts # list for this outboard.

Independent outboards Arndell park about $140 for the gasket kit from memory. Helpful guys aswell.

[Flickn Mad]

Ha ha the site says im a Morwong, they cant even spell mooron wight.

[zmk1962]

Agree with earlier comment that when you get to this much build up then the only way to get rid of it is to pull apart and mechanically remove. I don't know of any product that will dissolve it but keep the block intact. In general I've always been told that high water pressure just forces salt further into cracks etc. What you want is copious quantities of fresh water to dissolve away the salt. So +1 for flushing for as long as possible (and staying friends with the neighbours).

Re noise... silence using bucket/bin if the setup and location is convenient to allow moving a bin around, but if you are on a hose out in the street, or the leg is high then consider making up a silencer/muffler. I've posted my DIY solution previously here ... 

Cheers

Zoran

[Nolongeramember]

31 minutes ago, Flickn Mad said:

 

Even after cleaning it up the stat opens very little at idle.

A Drum would allow for the water to warm up, meaning more flow through the t stat.

It would also make a reasonable silencer so you may be happier to run it longer.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Some of the reasons the barrel flush is better. 

That’s right, the thermostat opens very little. You can flush for hours and still won’t remove all the salt as there is very little water flow going through the galleries. It’s inevitable that salt will build up inside over time. 

[Nolongeramember]

47 minutes ago, bizzyb said:

Any recommendations on where to pick up a cylinder gasket and cover gasket? Or better still, where not to buy?

I don't have a parts # list for this outboard.

Any Yamaha dealer.