55 HP Chrysler Outboard has no power in gear

[johnfarrow]

Hello all, I have a 15Ft boat with a 55 Hp Chrysler motor on it.
The model number is 557HG, Serial no: 6611

It will rev like crazy in neutral but as soon as i put it into gear, it just doesn't "take off". The motor sounds like it wants to fly but doesn't.
We recently hat to fit a new head gasket because water was getting into the cylender - that fixed that problem but the motor still has no power.

The compression is 190 in both cylenders & the spark from the coils will jump a 1/2 inch gap.

We have tried new plugs but still no avail. fuel/oil ratio is 50to1.

The motor starts quickly and idles well, no backfiring.

There is nothing blocking the carby up either.

Any sergestions would be greatly appreciated, Thanks

 

[byacey]

Re: 55 HP Chrysler Outboard has no power in gear

Does this have magneto or electronic ignition?
Even though you say the spark test checks out, it sounds like one cylinder isn't firing. If it's magneto, pull one sparkplug wire and short it to ground. Then start the engine. If it runs the same, there's a problem with the ignition you disconnected. If it doesn't start, replace the wire then remove and short the other wire. If it runs, but still lacks power, the problem is with the disconnected ignition.

I don't have any experience with the electronic ignitions, shorting the plug wires could possibly be harmful to the ignition module.

 

[Frank Acampora]

Re: 55 HP Chrysler Outboard has no power in gear

Well, It takes way more fuel to run under load than in neutral. That's one reason so many engines run well in the driveway (carpark?) and not on the water. An engine can turn 5000 RPM in neutral and still not get enough gasoline for operation in gear. So, if you have spark and the engine fires on both cylinders, check the fuel system. Not only the carb(s). Check everything: The strainer in the tank, the fuel line, the strainer at the fuel pump, the fuel pump diaphragm, the quick connect fittings, the float level, and grit or crud stuck in the inlet needle.

There is a strong possibility that a new fuel pump diaphragm may be needed--That would be the first thing I replace just on general principals--only 3 bucks U.S. (Carby? Aussie?)

 

[johnfarrow]

Re: 55 HP Chrysler Outboard has no power in gear

Hello byacey,
It might be Electronic ignition but im not 100% Sure.

I pulled the plugs out and they looked different.
1 plug had a thin layer of black carbon buildup
the other plug was not covered in carbon - like it wasnt burning fuel.
(PS: remember these are new plugs)
Could this be an indicaton of somthing wrong with the spark side of things or possibly a fuel/carburettor problem?

Could timing play a role with the power problems?

BTW we intend to get some more spark plug leads as these ones don't click onto the S/Plug as they should.

Frank Acampora: I will sus out the fuel side of things and get back to you, Thanks

Any advice would be apreciated

 

[johnfarrow]

Re: 55 HP Chrysler Outboard has no power in gear

Frank, I checked everything relating to the fuel side of the engine and it is all ok. the 1 thing that did catch my eye is the diaphram, it looks a bit loose and there is 3 to 4 strech marks on it, do you think it needs to be replaced?
I will get new spark plug leads and take it for a run to see how it goes,
Probably tomorrow morning.

 

[johnfarrow]

Re: 55 HP Chrysler Outboard has no power in gear

I just found out that it is magneto ignition, will test it soon