Exhaust leak
 

My boat has developed an exhaust leak & the RPMs are down. I tightened the manifolds which help but now the leak is back again so I’ll replace the gaskets. Just wonder if the exhaust leak would cause a significant rpm drop (500 rpms) also or should I be looking @ 2 separate problems.

i dont think an exhaust leak will cause the engine to loose power,sounds like something else is wrong.

dont over look this,if its down on power or it could be runnig lein and could be causing more heat out the exhaust which will cause the bolts to stretch a bit to cause the leak in the first place..

An exhaust leak won't cause a 500 rpm loss in power. I think you've got another issue. Probably too hot/lean and burned the exhaust gasket.

Thanks for the tip. If anything it seems to be rich with the sooty transom & plugs. Plug # 5 was lean which is where the exhaust leak was. I’m guessing the exhaust leak cause the lean plug? I’m going to do a compression check on that cylinder as well.

Still haven’t checked the compression but did notice the cap & rotor had a lot of build up which I cleaned. I’m hoping that is the cause of the rpm drop. I have the TBV & noticed the terminals are aluminum. Is there a brass terminal cap & rotor for the TBV or are they all aluminum.

Is it an EFI motor? If so that injector might be slightly clogged and would cause a lean condition.

Its carbed. When I replaced the gaskets I switched the plug & that cylinder was still lean after my next run. Think I found the RPM drop with the fouled cap & rotor but won't know till this weekend.

No PSI in # 7. Pulled the head & the intake valve is warped has a sucked in look to it. The motor did get hot @ the end of last season with a worn impeller . I'll clean the carb while everything is down as well. Would this be considered a burnt valve? I always thought burnt valves were exhaust valves?

Might as well pull both heads and do a top end on your engine now :) Your half way there already.

As so burnt valve or a warped one, well I would imagine it had to get real hot to warp....