If it was fuel related with that much RPM loss you would get a lean pop at full throttle. When was the last time you pulled the drive and checked the gimbal bearing. ANYTIME YOU BUY A NEW BOAT YOU MUST CHECK IT OVER. Either you do it yourself IF you know what you are doing or you pay YOUR mechanic to look it over. DON'T trust the seller or THERE mechanic. Static timing doesn't matter with a stock engine only MAX advance set to 34*.

Take off flame arrestor and have your buddy see if the secondaries open.

I've run into this with all the big three - Holley - Quadrajet - Weber/Edelbrock

Few of the boats wouldn't even get on plane . Ran fine though. LOL.

You posted while I was typing.

Quite the opposite. LOL.

Your advice was great !

Boat ran fine all last year since I bought it, ran fine this spring, then it started acting up... so gimbal wasn't checked since it started giving me problems as I leave the boat in the water. Can that really cause that much rpm loss?

"Take off flame arrestor and have your buddy see if the secondaries open." - Planned on doing this the next time I can get someone in the boat with me.

Thanks again guys for all the advice! Just got a compression gauge, so I'll be checking that also.

You say that you leave it in the water. do you get water in the engine compartment? Is there a trickle of water running down the transom under the engine? You may have a bad bellows and the gimbal bearing is under water and binding. The water would cool the bearing. You said you felt a vibration.

Believe it or not I do have a trickle of water running down the inner transom plate and thought I have a slight leak in the bellows, I planned on upgrading to a bravo 1 setup this fall. Didn't think the gimbal bearing could bind from a trickle of water... maybe that could be the problem?

I would think if a gimbal bearing was seizing enough to slow the motor down
A. You have 15 hp turning the drive and any extra resistance will slow it down
B. It would explode within 5 min

I would think if a gimbal bearing was seizing enough to slow the motor down
A. You have 15 hp turning the drive and any extra resistance will slow it down
B. It would explode within 5 min

Yeah I figured with all the WOT testing I've been doing I think the gimbal bearing would have let loose already if it was the seizing.

Checked timing today, I let it warm up to normal operating temp then checked it. Initial timing was about 2 degrees before TDC, advancing to about 24 degrees before TDC. so I set the initial at 8 degrees before TDC and the idle went up about 200 rpm, so I reset it. Total advance was about 30 degrees. I was worried to advance it any more because the initial would then be at about 12 degrees, wouldn't that be too high? The mechanical advance arms move freely and do not bind. Engine sounded like it had a bit more pep but did nothing to fix my issue.

Oh and the dwell climbed to about 27-28 degrees when I changed the timing, weird?

I let the engine sit for about 45 minutes to cool a bit so I didn't cook my hands taking out the spark plugs. Then I finally got the compression test done. 150lbs pressure on all 8 cylinders.

Now the only things I have not touched are the coil and the spark plug wires, guess I'm doing those next.