tm29

I have a Z33 W/twin 7.4 LX MPI W/bravo 1s. The problem that I can not figure out is that the rpm's do not match at all. At cruising speeds the starboard side runs about 300-400 less rpm's. and at wot about 500-600 less rpm's. So I read up on the forum about such problems and these are the things I have tried. both accelerator cables are in the WOT postion when throttle levers are maxed. next I switch props to see if its the props were it.where it would be in reverse and go forward etc etc.the rpms were right on the money and the sound of the engines was in sync. the props are 23p one is a quicksilver mirage and the other just says quicksilver both are 23p, not sure if that mattered or not. I have only had the boat for about a month and trying to figure this out. thanks for any help and suggestions

HeavyChevSS

Check your tach's, then maybe a compression check?

GO4BROKE

iTrader: (1)

Did the tachs read the same when you synched the engines by ear?

tm29

yes when I reveresed the props the tachs read the same and were in sync

tm29

its when I put them back like they are suppose to be the rpms are off and the sounds are out of sync only when i reverse them its all ok. does not make any sence to me at all could the props be mismatch or something they appear to be in perfect shape all except one is a quicksilver mirage and the other is just a quicksilver both are 23 pitch.its blowing my mind while it runs in sync reversed,and all out of wack when the props are on the right sides.

cooltoys61

One has more cup than the other? If your ear says in sync the tach must be right. Have you opened throttles to 3/4 and take off the flame arrester if carbed to see that the throttle position is the same? I guess you can do that on FI too.

tm29

if one has more cup than the other how come they are in sync when i switch props from one side to the other. I am all confused

obnoxus

Has this problem been there since you have owned the boat?

If so,, verify drive gear ratios are the same.

mcollinstn

Odd.

It is possible that one of your drives has bad thrust bearings for one set of gears. Not likely, but possible.

Mirage and Mirage Plus props say it on the hub. Mirage props are DIFFERENT than non-Mirage Quicksilver props. You may also have a trim issue where your indicators are not properly reading the same.

you SHOULD be running the same style of prop on both sides.

I say first thing to do is to make SURE both props have the same blade style. Do that before looking any further.

Andy

Not to sound like a dumb ass but when you say you swap props R to L you put the drives in reverse to go forward? Isn't that real tough on the upper bearings