Head temperature

[Escambia]

2001 Yamaha 115 2 stroke. Overheat alarm went off after about 2 hours of running. Turned motor off and back on, hit the throttle and motor went into safe mode with alarm going off.turned off again for about a minute and crunk it back up and no further issues. Has new thermostat and impeller. Cylinder heads are 120 to 125 degrees at idle. Is this normal or too hot...I'm about to worry myself to death about lol
..any help would be greatly appreciated

 

[Mrroo]

That temp is fine. If not a little low. Did it happen after the Tstats and impeller were replaced? If it's used in salt water, i'd do a couple good flushes with salt away.

 

[Escambia]

Yes sir, the stats and impeller we're changed last year. I have a poppett valve on the way to change also. It's used in salt water and fresh but mostly salt at pensacola beach fl(wife hates the river). It was the first time it's been out this year and I was concerned about the water jackets being clogged. Going to flush with vinegar as well in a few days after poppett valve replacement. Don't know if vinegar helps or not

 

[Sea Rider]

If engine has new mechanical parts such as impeller, thermostat, is well carb and timing advance synched, definitely has salt layer build up on all water paths throughout the power head. Vinegar must be 5% pure not mixed with water while engine runs on a barrel to help disolve salt layers, crusts to some extent. Better use Salt Away and check if didi its homework right.

If continues to run hotter or overheats with more use, will need to pull cylinder head, water lid from exhaust port and clean all internal powerhead water paths and remove salt formation mechanically.

Flushing engine after use with fresh salt water is no indication engine will never collect salt layers as one wrongly assumes, and that's from personal experience dealing with engines constatntly used in salt water.

Happy Boating

 

[Escambia]

I was sure trying to keep from pulling heads, but it's not that difficult of job just ordering gaskets is a pain. Is the temp 120-125 degrees idling on water hose for 20 minutes to hot?

 

[Mrroo]

I was sure trying to keep from pulling heads, but it's not that difficult of job just ordering gaskets is a pain. Is the temp 120-125 degrees idling on water hose for 20 minutes to hot?

That temp is perfectly fine. But best test is on the water. Running on the Muffs can cover up a pressure issue. Get that thing flushed out with salt away and recheck. But heads and such might still have to come off. Salt water sucks. Lucky we dont have that up here in the Great Lakes. But we have salt in the winter killing our cars.

 

[Escambia]

I'll be ordering salt away...I sure preciate it!!

 

[yamatech43]

If it was me, I'd want to know if it's running warm or not....just call me crazy. With the cowling off run the boat at speed for a while(or until alarms) and with motor in neutral put two fingers on top of head....you should be able to leave them there for at least three seconds. If it is overheating try Neutra-Salt from Volvo, we always found it to be the best, really amazing stuff.

 

[Sea Rider]

If you can perfectly fry an egg on top of powerhead, definitely is overheating. Has anyone tried Salt Away ? which were the results, did it worked out as advertised ?

These are internal hidden salt formations seen on a 2 cylinder engine run for 600 hours from new which has been flushed with fresh water for 10 minutes religiously soon after returned boating on salt water. Now imagine a larger engine how much salt formations can collect..



As seen extensive water flushing with fresh water won't do much at all, not even flushing constantly when out of the box.




Happy Boating

 

[Escambia]

Reference to your pictures. Is there anything to run through the motor to clean that off or would that be too far gone?

 

[Escambia]

Alright I'm bout to set fire to this thing. Running on hose for 20 minutes heads still reading around 125 (using laser heat gun). Alarm buzzer goes on then back off. Imeditly check temps again still around 125. Is it possible to have a bad kill switch or overheat buzzer. I pulled the lanyard from the kill switch just to see and motor kept running. Could this be my problem, and not actually overheating?

 

[Sea Rider]

The posted pictures is from a motor that has a flushing port build on the exhaust cover, it's flushed often with hose and adapter with high water pressure, as seen on pics didn't helped much to clear all those horrible salt buid-ups. BTW this motor was not overheating, was just a intenside preventive powerhead maintenance that's done at least at each 500 worked hours.

When any motor trully overheats due to bad thermo, excessive salt buil-ups inside powerhead, even clogging lower leg water intakes with kelp, plastic bag, will see the motor literally smoking, could even melt cable shields touching powerhead area.

Change temp switch if old, or remove switch and clean tip, could be rusted and not monitoring the temp correctly. Go for a Salt Away long flush on a barrel and a combo water spin full throttle soon after..

Happy Boating

 

[Escambia]

Temp switch? The sensors on both heads? Sorry for all these questions. I'm a cop and not a mechanic lol!!!! I don't even know where the temp switch would be at... thinking cap done fell off.

 

[Sea Rider]

Yep, temp switches or sensors, replace both with new ones preferably as won't know which one could be the faulty one triggering intermittently, personally would go that route, then Salt Away flush and a wot run as stealing the combo LOL!! Get a parts manual to check where temp parts are located, usually sit on powerhead's upper front.

Happy Boating

 

[Sea Rider]

Recapitulating :

Got me puzzled about thermos opening at 180 deg F when tested. Have read several Service Manuals from other larger OB brands and all those thermos opens at 140 deg F. If opening at 180 deg F the thermostats are working too slow cooling powerhead, 40 deg F lag difference might pull heat alarm prematurely ?

There are ways to correctly troubleshoot thermos and temp sensors, for that venture will need the Service Manual tech specs, if not will be a wild guess if both are doing their homework right. Swapping both thermos and sensors without having troubleshooting them correctly could end being costly, assume $ 200.00 but cheap enough for what a 115 OB costs.

Happy Boating

 

[Escambia]

I thought 180 was a little warm myself but I was taking that ol boys word for it. I know there has got to be better ways to check all that stuff than putting it on a stove.lol...i guess I really need to run the thang and if it goes off again pull the cover off and check it with my temp gun? This is my first Yamaha ever, mostly Evinrude man but that's how it goes. Every one's consensus is water pump even though water pump and thermostats were changed last year. Never done a water pump myself before. Doesn't sound hard but I have a tendency to screw things up just by looking at it.....

 

[Sea Rider]

Try Salt Away cheapest solution and for the record post if cancelled the temp sensor triggering itself.

Happy Boating

 

[Escambia]

I actually flushed it twice day before yesterday with salt away. Did one flush through the flush line on the side and another one through the muffs on water hose. Probably gonna do one more before going out again( hopefully soon).