loss of rpms, 2010 Honda 50

H

hansonby

New member
[please excuse lack of knowledge of proper mechanical terms]

Our twin Honda 50's have always run identically until now.

We've been out five times this season for several hour/day runs and everything was fine until the last two times.

The port engine is now running at a lower rpm than the starboard engine when at equal throttle. It does seem to run smoothly.

When the starboard is at, say 4400, while the port engine is at, say 4000 (at equal throttle), the vessel doesn't pull one way or the other.

While they both idle at ~980 rpms, the starboard engine doesn't get up to the same rpms as the starboard. E.g. - when I throttle the starboard to 4000, at an equal throttle the port engine is about 3600.

At WOT the starboard gets to 5000 and the port just to maybe 4600.

When I drop the control on the starboard engine to WOT one hears a nice "roar," whereas on the port, the roar isn't as good.

We buy all our gas at our home marina, and it's E0.

I looked at the port fuel filter. It was about 3/4 full of a clear liquid that had a petroleum odor. Water? It didn't look like gas. After 5' of observation I did not detect any gas/water separation.

The filter itself looked great - no sediment, etc.

If a filter LOOKS good, is it doing its job?

Since the filter cartridge was only 3/4 full, does that mean there is no more water in the system (assuming the clear liquid I found is not normal)?

Would a can of Stabil do any good?

If I replace the fuel filter (getting one this AM), will that solve my problem?

Thanks for any comments.

Byron Hanson
 
Byron-

If, after

1) changing the filter(s) and

2) draining the bowls, and

3) adding Stabil, or better yet, a fuel system cleaner like Sea Foam (Stabil is a gas preservative),

4 ) there may be secondary fuel filters inside the individual engine cowlings that need to be be checked, cleaned, or replaced.

5) also, be sure to check your props for dings and/or bent blades. A fairly small ding or bent blade can cause a significant drop in rpm and performance.
You don't have to hit a full-on deadhead to get a bent prop, either.

I'm sure there will be more ideas to follow.

Good Luck!

Joe. :teeth :thup
 
It's hard to say for sure. I'd check the spark plugs too while you are at it to see what they look like - you might have a fouled one that works ok at idle but misfires under load. It also could be a linkage problem....tough to tell.
 
It would seem that any issue is related to the port engine, so that would to eliminate any common system, fuel or fuel tank etc. If the boat is not pulling one way or another, that could be a tach issue and your true RPM has not changed. We now have a single 50 and I have seen the tach bounce around occasionally for no identifiable reason. So that might be another detail to review.
Jack
 
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