RPM Issues

trich11

First opportunity actually get the boat out and run yesterday. Five people, nearly full tank and plenty of beer. Had some storms come up so I decided to run south to get away and when I powered up I noticed the port engine was producing more RPM's than the starboard. Did the tach tap, several times at different levels and nothing. Even at 7-8 MPH it was two hundred higher. Second thing was the port engine seemed to be louder than the starboard. Ideas on where to start?

craigswardmtb

Are the engines synced and do you know they're trimmed evenly?

trich11

Trimmed properly. Tried it at various trim settings. Sync'd properly.

Black_Diamond

You'll get odd sounds when they are out of synch. Assuming your tachs were correct, it could be a throttle adjustment. I'd start with making sure they were in synch as noted above.

brianluck

I've got issues similar when I have a bad fuel filter makes it harder for me to match Rpm's

trich11

It seems that a fuel filter would cause it to run poorly at all times. The engines both start properly and idol smoothly. Any thoughts on a cap and rotor?

mvn

trich11 said:

It seems that a fuel filter would cause it to run poorly at all times. The engines both start properly and idol smoothly. Any thoughts on a cap and rotor?

Not necessarily true.  At low speeds, the filter can pass enough fuel.  At higher sppeds, the filter can't flow enough.

Mark

trich11

This bears checking out as I have not changed the fuel filters on the boat in 3 years. Any ideas on the fuel filter location on a 2002 342?

mvn

Seriously??!?  What engines do you have.  Chances are they will be located on the starboard side of the engines down low near the front engine mount.  But then again, I'm not familiar with cruisers per se.

Mark

trich11

350 mags. If they are down that low that means holding the wife by the ankles and putting her to work.

mvn

Have a look here......

Mark

trich11

I thought you meant there was a separate fuel filter besides the fuel water seperator. I changed my separators last fall and used Stabil. I will get out the glass bowl and give them a look. Thanks Mark. 

mvn

You may also have separate in-line filters (see attached). Someone here with an '02 342 and 350 Mags will probably have better advice.

Mark

rinker312

I have the same problem, my RPM gauges are always different, sometimes way different, but after cruising for a while they usually settle between 100 and 200 different from each other.  I have always ignored them and just kept the synch gauge in the middle, never really noticed one engine being louder than the other.  What exactly does the synch gauge do differently than the RPM gauges?  I always thought it was reading the RPM's and my RPM gauges just suck. 

trich11

The stock Faria tachs' are known to be a pain in the a** but in the past if a tach went a bit heywire I could to the tach tap and it returned to normal. This time I am pretty certain they were reading right as the port engine sounded like it was turning around 800 more RPM than the starboard thus the louder sound. In the past, my engines when attempting to plain ran up at a pretty equal pace with the throttles aligned side by side. This time to achieve an equal RPM display I had to offset the throttles over an inch. This is a new condition.

l-skynyrd

Trich....

I might be wrong, but I think the sync gauge is measering the thrust from each engine, not RPM. I got into some weeds about month age and used the sync gauge to determine which drive had the weeds on it. Did a bunch of carzy things and got rid of the weeds. When the drives are not in sync with nothing on the props you can hear the difference in the engines when they are in sync. This is how captains used to do it before electronic gauges. When I have the drives in sync my tac's never read the same (cheap guages).

So I think you might have a problem with the props or it might be an engine problem or in rinker 312  problem it might be cables.

 

Len