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]

Another thing to check

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

[captain kenny]

Fuel

Are you running fuel from your tank?? Do you have an electric pump?? Fuel left in a boat tank fouls, left for years it is useless. I run fuel from an outboard tank to the electric pump and to the polishing filter(new) then to the carb. test the flow of fuel into a glass jar to make sure you are pumping. If this doesnt help remove and clean the carb then try again. All the answers are good and mine is run good clean fresh fuel!!!

[RobH2]

Wow, lots of good suggestions. This is a lively forum. I like the participation here and appreciate the input.

Responses:

--Fuel is OK. We used 50 gallons bringing here to my slip so it's flushed and fresh. Flow and filter OK as I've tested that.

--We ran without a water lift muffler as it had a crack in it that we discovered during the delivery. Once here we installed a new muffler and the lugging is identical.

--Main jet is OK as I've removed, disassembled, cleaned and reinstalled the carb twice now.

My next step is to check the distributor for a crack, check the proper wiring of the plugs, check the advance mechanism and check the compression with my finger for a stuck valve.

Thanks everyone...

[wlevin]

another thing to check

We had your symptoms once, and it turned out to be a cracked set of points. The little pad that makes contact at the end of the arm was still hanging on, but was hinging when it was pulled away from contact. You couldn't see it without close examination. In fact, we didn't figure this out until we changed the points just for the heck of it (we'd tried lots of other things, and had spare points anyway) and vroom. Power.
Bill and Jeanne
T-34C #453
Otter

[Marian Claire]

If there is a blockage in the exhaust it will probable be before the water lift. The wet/dry connection could be the problem or the hose between the wet/dry and the muffler can separate and the inner lining collapse. The hot section needs to be removed from the manifold to really check. Good luck. Dan S/V Marian Claire

[roadnsky]

Rob-
As Dan just said, try disconnecting the entire exhaust.
At the EXHAUST FLANGE (see pic)

It'll be noisy, but if the engine runs better, you'll know to get into that exhaust.
As Dan said, start where the cooling water is injected and work backwards.

[RobH2]

Ok, I have some info to report.

"sastanley" suggested that I pull each spark plug wire individually to see if all the cylinders are behaving. When I pull the wires on either cylinder 1 or 2 there is NO change in RPM or sound of the engine. When I pull 3 or 4 the RMPs drop significantly and it's obvious that something is missing. So cylinders 1 and 2 are malfunctioning it appears.

So "sastanley" you said "...if you pull a plug wire and notice no change, we then have a symptom to work with."

FYI, to be proactive I installed a new distributor cap, points, condenser, spark plugs and spark plug wires. That eliminates those from the mix.

Now that I have the "symptom" what do I do next? Are my valves stuck?

[RobH2]

Ok, I'm getting better with this forum. I'm reading about stuck valves and exhaust blockages in more detail. I'll check those out tomorrow.

Thanks again for pointing me in the right directions.

Rob

[Kurt]

If your engine is suffering from increased exhaust backpressure (exhaust blockage) you will notice reduced RMPs both under load/in gear and in neutral. You mentioned that you can rev the engine up to normal rpms in neutral, but no in gear. If that is the case, I would bet against elevated exhaust backpressure as causing your significant issues under load.

[thatch]

V-drive or direct drive?

Rob,
Is your A4 a direct or V-drive engine? The reason I ask the question is that most of the time cylinders #3 and 4 are the ones which tend to have valves stick. This is no doubt because of (in a direct drive motor) their closer proximity to the water inlet in the exhaust system. On the other hand in a V-drive version cylinders #1 and 2 are the nearest to the water inlet and might exhibit the stuck valve syndrome sooner. It certainly does sound like you are headed in the right direction with your troubleshooting.
Tom