270 Crusaders can't match RPM at WOT

[62jpod]

Port engine max is 3600 RPM while I can get the Starboard side up to 4200+ easily. Has anyone encountered this? I am going to check timing, throttle cable and prop match but wanted to see if there were any other ideas. 270's with Velvet Drives.
Thank you, John

[Stripermann2]

John,

Check all the basics, plugs, filters, timing. Do you have points or electronic distributors? Mechanical advance, springs are prone to rust up, gum up and stick.
Also, have you tried running both engines from the same tank, with the fuel manifold closed to the others? This may lead you to a Anti-siphon valve. Been there, done that...there also many posts on similar issues.

[captainmaniac]

What throttle positions are you in when you get those WOTs? If you synch the engines at lower RPMs (3000, 3200, 3500) are the throttles even or is one more advanced than the other?

I had a problem a couple of years back where I had one distributor that simply wasn't advancing (advance mechanism was seized). Between idle an WOT I was only getting 1 or 2 degrees of advance. I couldn't get more than 3000 RPMs out of that engine no matter what I did with the throttle. At a given RPM, I found I had to advance the throttle for the bad engine (distributor) more than the other one to synch the engines. Bought a rebuilt distributor (and sent mine away for rebuild to stash away as a spare) and haven't had a problem since.

[62jpod]

Thank you both for your help on this!

It is Interesting that you have both zeroed in on the distributors. I have yet to look at them since I bought the boat in August but I will check it out and post my findings. Not sure on type or vintage, with only 300 hours on them I'm thinking they are original from '88. I've changed oil/filters, fuel separators, plugs are as yet unknown, I will change them out. Makes me think I should I just should I upgrade to the latest technology distributor.

I have been running on either two front or two rear tanks. I will try running on one and see what happens, had to pump bad fuel out of one when I bought the boat.

Throttle position is uneven when engines are synched regardless of rpm. Although at idle it is just slightly different. When I power up, I need to advance each at a separate rate in order to maintain a synched acceleration.

Thanks again!
John