Burning smell at high RPMs?
07-20-2015, 07:39 AM
#31
Still had the smell at WOT. Slowed down, felt the exhaust elbows. The port was luke warm, could hold my hand on it all day long. Stb, was hot to the touch, could hold my hand on it for about 5 seconds. I decided to look for blockage in my cooling system. detached all the hoses at the normal spots by the power steering cooler, cool fuel, oil cooler, exhaust manifolds and removed the thermostat housing. Everything was fine, not issues or blockages. I change the thermostat while I was in there. My guy at the Marina said it can be normal for one side to be hotter than the other as long as it's not too hot, like over 170 degrees. I haven't been able to take it out since. I'm gonna get a heat gun and see what the temps are. Maybe it's a little oil leaking out of a valve cover or something.
07-20-2015, 08:05 AM
#32
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Not really agreeing with your guy, with that big of a variance in temp there is something wrong, both banks should be within a few degree's of each other
07-20-2015, 11:10 AM
#33
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Still had the smell at WOT. Slowed down, felt the exhaust elbows. The port was luke warm, could hold my hand on it all day long. Stb, was hot to the touch, could hold my hand on it for about 5 seconds. I decided to look for blockage in my cooling system. detached all the hoses at the normal spots by the power steering cooler, cool fuel, oil cooler, exhaust manifolds and removed the thermostat housing. Everything was fine, not issues or blockages. I change the thermostat while I was in there. My guy at the Marina said it can be normal for one side to be hotter than the other as long as it's not too hot, like over 170 degrees. I haven't been able to take it out since. I'm gonna get a heat gun and see what the temps are. Maybe it's a little oil leaking out of a valve cover or something.
Finally changed the plastic pump housing and problem was solved.
09-07-2021, 10:15 PM
#34
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Did you ever find out what was causing it?
I’m experiencing the same thing with my 35 fountain lightning I’ve got twin merc 525 EFI’s my boat is an 05 And we have flush the cooling system I’ve even replaced the Headers. When I run the boat over 4000 RPMs I get a strong burning rubber smell and as soon as I back it down it seems to dissipate quickly. My mechanic is taking it out on the water tomorrow with a temperature gun to see if he can determine what is getting hot as of now we’re not sure Which engine it is coming from. We are supposed to be leaving for the lake Cumberland Poker Run this Thursday and I am trying to figure out what’s going on, hopefully in time to make the run. We may try replacing both the impeller housings to see if that solves the issue.
