I have a Baja 272 I just bought with a 502 that runs great but when I start running over 4500 RPM's I get a funny smell that I think is possibly a rubber smell. I shot the risers/manifolds with a head gun and everything was running around 150-160 degrees. I see similar threads of peoples saying it could be the coupler? How do i check to see if that is the issue without pulling the motor, or is that even possible? I also saw another thread where someone said they replaced the impeller and it didnt fix the issue but then they replaced the plastic housing and it did fix it.... Any insight on this issue?!

Thanks,

Do you have rubber hose connecting the risers to the tips ?, I had a 2000 272 back in the day fun boats

yes it does have the rubber hoses connecting the risers to the tips. I shot those too but do not remember the temp. It was less than the risers though. You think it’s the rubber melting a little? Why would that happen?

coupler?

Id pull one off and see if its deteriorating from the inside

Maybe, how do I check that without having the motor pulled?

You can pull the drive and take a look see, but you cant see but about 4 inches of the coupler and the splines, do you have good water flow out the tips ?

water flow does look good. I did just have the gimbal and bellows replaced they didn’t mention anything about the coupler.

Usually once a coupler starts going bad, it progresses rapidly. I'm sure you checked belt tension. It's manual adjustment, not spring loaded.

What kind of exhaust is on it ?

Also, i’d check inlet side to oil cooler for impeller ir etc debris. Many peeps don’t remove the pieces when they have an impeller blow apart.