No Power and no RPMs

[RobH2]

I have a older C&C Invader that I've recently purchased. I've sailed for years but this is my first ownership of a boat with an inboard engine. I've only had the old gal for a few weeks and haven't pulled her yet as the yards are still full of winter storage for a few more weeks.

My problem is that I can't develop RPMs nor power. We delivered the boat 160 miles to my slip and she would not go over 3.9 knots. Yes, it was a long trip. We assumed that the prop was fouled and that the bottom was a shag carpet.

Today I had a guy use a fancy underwater video camera to take a look. The 3-blade prop looked perfect. There were no barnacles and nothing was wrapped around the shaft. The bottom was bumpy but not overgrown.

What could be causing this? Since I'm ignorant, is there a shaft bearing that could be frozen and causing extreme friction? Could the cotter pin of the prop be sheared and the prop is spinning on the shaft?

My engine will REV up very nicely in neutral so I know it's running fine and capable. However, when in gear, as I throttle up I can barely hear an RPM change and the engine is just lugging. It doesn't quit but it's just never REVs up.

Any ideas?

Regards,

Rob

[sastanley]

Rob,

The first thing I'd try is with the engine in gear and lugging, pull each spark plug wire one at a time, and see if there is any difference. This will tell us if each cylinder is pulling its share of the work (load)..if you pull a plug wire and notice no change, we then have a symptom to work with. This trick is sorta cheating between a compression check (stuck valve/ring) and ignition (bad plug or wire), but no change may indicate one of the cylinders is not firing correctly.

Here is a link to a FAQ from Moyer's site..you've already done one of these. (check prop)
http://www.moyermarine.com/faq/11.9.html

This engine will often sound great in neutral, but when you put load on it, other problems may surface..

I am sure others will chime in too.

[RobH2]

Thanks Shawn. I will do that test and report back.

[Marian Claire]

Could this be the old clogged exhaust problem? Try running it with the exhaust disconnected from the manifold. Dan S/V Marian Claire
http://www.moyermarine.com/faq/1.1.html

[Baltimore Sailor]

My first guess: a lean condition. Take out the main jet plug and pump a cup of gas through there and see if anything comes out. Be careful not to lose any parts when you take out the plug.

I had a similar event with my engine last year after it sat for a month getting work done at another marina. She started right up and revved fine in neutral, but just died when I put her in gear. I finally limped her home (just down the creek, thankfully) by pulling the choke nearly all the way out. After I got her home and could tinker a bit, I opened up the adjustable main jet a bit more and she was back to her old self.

You probably have the fixed main jet and not the adjustable, so removing yours and flushing it a bit is your only option. It's an easy thing to check and may pay off.

[thatch]

Rob,
It is possible that the advance mechanism in your distributor is frozen. If this is the case your engine will start normally and seem fine but will develope very little power under load. Since I see from one of your photos that you have good access to your distributor, the easiest way to check it's centrifical advance is to remove the distributor cap and see if you can rotate the rotor slightly in a clockwise direction (approx. 3/8 inch at the tip). It should spring back to it's 0 degree position after this test. If your fuel and ignition tests all check out okay it might be worth doing a "power tuning session" where one person rotates the distributor while the helmsman checks for maximum speed.
If you don't already have one it might be a good time to buy Moyer's service and overhaul manual.
Tom