Have a question about popping sound at idle and engine running rough , also back fires through exhaust at times ? Not always! Any suggestions? Need help and a great mech. THANKS!

What motor is it? Carb/FI? Where is the boat?

Engine is 502 carb crate motor,merlin heads and intake,crane roller rockers Stainless Marine gen3 Ex. thats all I know about the engines. ST. Pete . Fla. THANKS!

Sounds like a bad valve or broken valve spring. Don't
know if you have adjustable rockers,but if so,one
may be tight.

Try a compression check on the engine.
I have had a valve hang on the guide and just kissed
the piston. Pulled heads and there it was.



Good luck

Do a leak test. I'd guess bent valve too.

Dave

How many hours on the motor? Another possibility is a worn cam lobe. Are you running a roller or flat tappet?

Thanks for all the advise,I still need someone to do the work. Anyone know a great mech? Let me know. Thanks

I know a guy in Clearwater that worked on my 2004 Spectre36 w/900hps; he did not do very much but he also builds custom motors and boats etc... Seems as though he should know quite abit. He is fast and reliable as far as my experience.

Good Luck!

Ray Hanke
Force 10 Marine
727-573-7666

It's all been covered.

Cam lobe or lifter issue.
Hung, stuck, or bent valve.
Broken valve spring.

best of luck.