Help! Port engine has a high speed miss
 

I have a 30' OL with the twin 496 HO's

Yesterday while out on the boat the port engine began "popping" at around 4000 and above RPM. At lower RPM's it seems fine.

Both engines have 140 hours on them. To my knowledge the fuel filters have never been changed.

STBD engine runs fine.

Any ideas on what I should be looking for?

change the fuel filters first,,

Ignition probelm. Check wires, change Plugs, Check Cap & Rotor.

When it does it how much does the tach drop?

I will do that, thank you!

I checked all wires and they are all connected. Will change plugs also. Distributorless ignition so no cap and rotor. Thanks for the tips!




It will fluctuate/drop 300 RPM's when the throttle is held at 4000 RPM

http://www.offshoreonly.com/forums/g...4600-rpms.html


You should change your fuel filters but doubt it is fuel.If the tach is dropping that fast you are probably losing power to the ignition system.Linked a thread had similar problem a few years ago.
But you really have to go back to basics sometimes but I believe its ignition.

miss the 496HO's.... lol

Did you figure out what was causing the issue? We are experiencing the same thing at 4000 rpms, but without the rpm drop. We just have a popping sound that starts around 4000 rpms. Motors run great otherwise.

Check the Fuel pump, my brother just went thru/ this last week!

Have someone check your injectors as well...A friend of mine just went through this as well.