I recently purchased a 25 outlaw 2001 with a 502 Mag MPI and noticed a slight burning smell when I run the boat hard around 4500 - 4600 rpms. I'm getting 64 on GPS with a 23 mirage and over 1/2 tank of gas. The speed seems normal to me. I don't push it for too long, only short spurts. Any suggestions of what might be causing the smell? It seems to go away pretty fast after I drop the rpms. Motor and drive only has 300 hrs on it.

Could be water flow issue, I presume you have some rubber exhaust hose connecting to the tips ?? my 33 OL did the same thing, put a sea pump kit in it and it was ok.

I put a new raw water pump kit in it to start the season. It does have to stock exhaust with capt call. Corsa tips with weighted internal flappers(I just put them on this season also). Internal flappers in the y-pipes all good when I put the new tips on. Rubber all seemed good then.

Could it be the serpentine belt? How do you know when they are going bad?

Does it smell like oil? Or electrical? Have you run it hard than come to a stop and notice any smoke or try to isolate a general area it coming from? Any oil leaks?

That's the smell of burning money. Every boat has that. It only gets worse.

Need a better script of what the smell resembles

Do you have closed cooling ?

What is your temps running at

What is the volts charging at / alternator and is the alternator very hot to touch

any oil leaks and or pwr steering fluid leaks

exhaust manifold gasket leak ?

Too hot of an engine paint burning especially hot running exhaust manifolds and or rubber components ?

Any pulleys making noise

Belt slipping - check tension

The list can just keep going on for types of smells inside an engine compartment - just saying

If the rubber in your exhaust gets hot, it gets very stinky in a hurry. Check your water system thoroughly for clogs, you may have sucked up some debris. Power steering cooler is a usual suspect for gunk to get stuck up in and restrict water flow to the engine.

It's a 502 mag mpi stock. Open cooling. Temps are from 165 - 175 when running at high rpms. I don't hear any pulley noise and there are no oil or fluid leaks in the engine compartment. The smell is hard to classify, but I would say it's closer to rubber/electrical than an oil burning smell. How can I tell if the exhaust is getting too hot? It has normal stock merc exhaust with corsa capt call. Will the rubber on the exhaust hoses get deformed if they are the cause of the smell? When I took the exhaust off to replace the tips this year, I did not notice any issues with the hoses.

Trim your drive all the way down while the boat is out of the water.

Now have your 250 lb buddy stand on the cavitation plate and bounce up and down.

If you see the drive moving and the transom flexing down by the bottom of the boat what you are smelling is the coupler