Engine Missing?

[bjperry]

What's the best way to tell if I have an engine miss while running on muffs? I'm rebuilding the boat so can't just take it to the lake to see how she runs, but just replaced the powerhead and want to make sure she's running on all cylinders before proceeding. The engine is '78 V-6 150 Blackmax. Anyway, I have a hard time telling by listening since the exhaust is loud when not in water. I'm hoping someone can give me a good diagnostic tool so I can make sure they're all firing and burning. I've got good spark on all of them and rebuilt all three carbs recently so I don't imagine I've got any fuel issues. I know most say that if you've got spark and fuel you're running. Just want to check.

Thanks.

 

[emckelvy]

Re: Engine Missing?

With the engine off, pull one spark plug wire at a time, stick an extra spark plug in the boot and ground to block.

Then fire 'er back up and if that cyl was pulling its load, you're gonna hear the difference.

If no diff, then that cylinder's not doing its part. Repeat for the other 5 cyl's.

Note if you have a timing lite (or a firing indicator) you can use that to tell if each cylinder has good spark under compression.

Don't forget new impeller, adjust timing to specs and follow mfr's break-in procedure using double-oil!

HTH.........ed