Engine erevs well no load, will only do 900rpm in gear

[Bryan Howell]

So happy today, altho getting a late start on the season went to the boat, it actually started pretty easily, ran great at the dock. Rev'd easily with no load. Cast off, crept out of the slip, gave it more throttle and nothing. Slight bump in rpm from idle speed to about 900. Full throttle, 900 rpm. Mid throttle 900. Needless to say I was creeping with wind at my stern.. Coming back in, wind in the face, barely made enough headway to get in the channel to my marina.

Lots of work last year, new electronic fuel pump, fresh plugs and wires, end of season new coil (Moyer). This is first time out with the new coil, the old one was overheating and shutting down, (tip from this forum, thanks).but the motor was putting out plenty of rpm under load, could make 5-6 knots under power.

So what one earth is causing my motor to just refuse to rev up under load? It is not missing, smoking, just will not rev under load.

Thanks in advance.

[JOHN COOKSON]

Were their any additional maintenance\improvement procedures, other than the ones mentioned, between the time of normal running and poor running?

TRUE GRIT

[thatch]

Two things that would cause a lack of power are incorrect plug wire order,
1,2,4,3 or stuck distributor advance weights. During a winter lay-up, it is not unusual for them to rust themselves in place.
Tom

[zellerj]

Also collapsed exhaust hose would cause engine to bog.

[Dave Neptune]

Bryan, did you try pulling on the choke when some throttle was applied? I have a feeling it is the carb that is plugged up a bit.

What Thatch said is good advise and should be checked, then go to the above.

Dave Neptune

[Bryan Howell]

Were their any additional maintenance\improvement procedures, other than the ones mentioned, between the time of normal running and poor running?

TRUE GRIT

Nope, but I failed to mention new carb late in the season last year. 100% new exhaust hot and wet mid season last year. All predating the poor running.

[Bryan Howell]

Two things that would cause a lack of power are incorrect plug wire order,
1,2,4,3 or stuck distributor advance weights. During a winter lay-up, it is not unusual for them to rust themselves in place.
Tom

Electronic ignition. As for plug wires, unless gremlins got in my engine bay over the winter do not think that was messed with, but it is an easy check.

[Bryan Howell]

Also collapsed exhaust hose would cause engine to bog.

Good thought, but as I replied earlier, brand new exhaust system.

[Bryan Howell]

Bryan, did you try pulling on the choke when some throttle was applied? I have a feeling it is the carb that is plugged up a bit.

What Thatch said is good advise and should be checked, then go to the above.

Dave Neptune

Dave, I did trying pulling the choke, really made no difference. I kind of suspect some gunk or more likely fuel shellac buildup in the carb as well. Grrr....... Put SeaFoam in the fuel before winter, but who knows how well that mixes.

Anyone know a good way to clean a card without taking it off and apart? I have used some spray carb cleaner on my generator a couple of times that seemed to help.

[Dave Neptune]

Bryan, there is no way to clean the inside where the KRAP is without a disassembly. Be very careful with the float adjustment as it has much influence on this engine. It is a very simple carb and a kit is a must because of the gasket. Also be sure the gasket seals around the center where the emulsion well is. The e-well is where all of the mixing with air happens and if it leaks the carb will not work properly.

Lots of info on the forum regarding the "carb rebuild".

You may just have a main jet plugged up which is accessible on the bottom of the float bowl, may be worth giving it a poke with a small piece of wire. But it may just plug again which is why I recommend just doing the rebuild/cleaning.

Dave Neptune

[ndutton]

I'd do five things, all mentioned or hinted at previously:

1. Pull the EI plate in the distributor and lube the advance weights. They probably need it anyway. Easy to do.
2. Pull the carb, disassemble and clean thoroughly. Also easy to do.
3. Change the fuel filter, inspect the contents of the old filter in a glass container for debris. Should be easy to do.
4. Replace the fuel in the tank with fresh if the debris inspection in #3 indicates.
5. If no resolution after the forgoing, install an exhaust backpressure gauge
   

   http://www.moyermarine.com/cgi-bin/shopper.cgi?preadd=action&key=EXHT_04.2_492

   
   http://www.moyermarine.com/cgi-bin/s...ey=EXHT_04_127

At this point my money is on advance weights or dirty carb.

[Bratina]

I'll add to the great advice given above to remove your plug wires one at a time and see if the engine pitch changes. I chased carb problems for a good while until I realized that the plug in #4 (which was almost brand new) wasn't firing.

I'll also add to check that the packing gland wasn't tightened over the winter layup. Does the prop turn easily by hand when the engine is off and it's in neutral? Does it drip a little at rest and when running, and not get hot when you're in gear?

[sastanley]

Bryan, I have been TOTALLY amazed at the amount of sea growth on my boat bottom and prop this year. I did a bottom job in July 2016, and I have decided after diving the prop last week (I could not get more than about 1,400 RPM), I am just going to haul the entire boat. Too much to do in the water.

My theory is it did not get cold enough here on the Chesapeake this winter to "kill off" or slow down the seasonal growth. I had a subroll sized pile of barnacles all the way around the waterline on 8 month old bottom paint.

Maybe try a short haul and see what you find.

[JOHN COOKSON]

This Is Disgusting

. I had a subroll sized pile of barnacles all the way around the waterline on 8 month old bottom paint.
d.

What bottom paint did you use?

TRUE GRIT

[sastanley]

John, I used the same West Marine CPP I've been using. I know it is not the high $$ stuff but it has served me well..I did the same procedure as the last several haulouts.