One engine has 800 rpms higher at wot

"Boat = 29 phoenix, twin crusa

"Boat = 29 phoenix, twin crusader 5.7 carbed power pack 300hp. This problem began after repower. Prior to repower, rpms wot were the same.(4200)with 270hp. Props just reconditioned and bottom clean. One engine will get to almost 5000 the other 4200.( the manual says 5000-5200 by the way, which seems awfully high) I thought it would correct itself after break-in, but has not. The engine that does not tach up requires more throttle to get to the same rpm, thus being less efficient on the floscans. The boat starts great, runs great, just one engine isn't as strong. I have not compression checked. The timing marks on both engines seem way off. On the strong engine, we had to time it by "feel" and adjusted forward until the spark knock and backed off until it went away at 4000 rpms. My theory is that the weaker engine timing is slightly retarded. I've never messed with the timing on the weaker engine since it has not any problems except being a little weaker. Should I compensate for rpm difference by pitching one prop more than the other?"

"Absolutely not! If you are h

"Absolutely not! If you are having severe chest pains would you crank your finger in a vise so you forgot about your chest pain?

You need to get the motor straightened out. You have already admitted that you don't know if the compression is good and you don't know if the timing is right.

If there is, and it sounds like there is, a problem with this engine and you change the prop to allow it to run at 5000 RPMs, you better wear a bullet proof jacked while boating, cause it IS coming apart.

P.S. If you have bi-directional gears, swap the props, change the direction of the gears and recheck the RPMs then (after setting the timing and checking the compression) this will confirm the accuracy of the props."

"Rick, you should be in comedy

"Rick, you should be in comedy and boat mechanics. LOL. I don't have bi-directional gears. How exactly would I check timing given that the timing marks are not accurate ( according to two mechanics) I don't understand the procedure for a vacuum gauge that I've read about. Please walk me thru how to time it correctly. In my area, if the engine is not an outboard or in a houseboat, the mechanics don't know squat, and the boat is not trailerable. Now one more piece of info that could tell you something, In an earlier post, I was escaping a bad storm running the boat hard and the "weaker" engine shut down, spit, sputtered - tach went from 3900 to zero, then when I backed it down it popped back to 800. It sounded like the motor blew. I tried again and it died at 2000 rpms and popped back up to 800. It sounded like I turned the key off, then it restarted on its own. I slowly accelerated to 3400 and it ran great home and the rest of the week. I've never brought it back up to 3900 again though. Does this shed any light on anything? I thought the lightning hit the water,went up the shafts and disrupted the ignition."

"Comedy is much less demanding

"Comedy is much less demanding but it doesn't pay the kids tuition bills.

It actually sounds to me like you ran her out of fuel, either due to a dirty filter or a restriction of some other type. This could be a delaminated or kinked fuel line, a clogged tank vent (if twin tanks) or even a poorly adjusted carb float.

Regarding the timing: I don't know why it can't be set normally but I'll assume the timing marks are too rusty and the balancer has spun.

First you need to verify TDC (top dead center).

You will need a piston stop. These are inexpensive and available at most any automotive parts store. Remove the spark plug from #1 cylinder. Install the piston stop. Using a socket on a breaker bar, rotate the crankshaft until the piston contacts the piston stop. Using a sharpie, put a mark on the balancer at a specific reference point on the block. Now rotate the crank in the other direction until the piston contacts the stop in the other direction. Using the same reference mark on the block, mark the balancer again. Accurately measure and mark the exact middle of your two marks. Use white paint and a fine brush for this mark. If the engine timing marker is still in place on the engine and you are able to use it for your "reference" spot on the engine, this new mark should line up with the original mark on the balancer. If it does not, the balancer has spun.

Now that you have your balancer marked it's time to set the timing. If you can't read your original marks you will need an adjustable timing light. Set the light at the desired setting as per the engine manufacturers specs, usually 8 or 10 degrees BTDC (Before top dead center).

With the light connected to #1 cylinder and the spark plug back in, start the engine. Following the proper sequence for setting timing, rotate the distributor until the light indicates the mark on your damper is aligned with your original reference mark.

When this is done, lock down the distributor, recheck the timing and you're done.

It sounds complicated but it will make sense when you do it.

Good luck,
rick"