73 Johnson Seahorse 2 HP help

[fishingfrenzy]

I'm doing my first motor project and love it so far. I'm working on a 73 Johnson 2 HP, and wasn't getting spark so I dove in. The carb was rebuilt so that was clean. Looking under the flywheel, the electrical system has been replaced before (not sure when) but probably within the last 10 years. The point gap was set at .010 so I reset to .020. I guess my problem now is I'm not sure what to do next...any ideas?

Under the flywheel

Moving forward powerhead was taken off to replace the seal, is it supposed to be this dirty inside the casing and on the driveshaft?

Thanks much for any tips or suggestions!

 

[tashasdaddy]

Re: 73 Johnson Seahorse 2 HP help

actually looks pretty decent, not a lot of use. coil, looks good, points could have kept it from firing. set plug gap to .030, it should start, if carb is not gunked up. consider impeller replacement.

 

[freddyray21]

Re: 73 Johnson Seahorse 2 HP help

agree replace the impeller since you have it apart. Those impellers for the small motors are dealer only as Sierra does not make one that small. Should be about 15 dollars at the dealer.

 

[fishingfrenzy]

Re: 73 Johnson Seahorse 2 HP help

Thanks for the replies guys, impeller was also replaced. Any idea why there was so much buildup in the casing?

 

[freddyray21]

Re: 73 Johnson Seahorse 2 HP help

the exhaust and water mix and exit the case. You are just seeing carbon. Nothing to worry about. Carb cleaner will get rid of it, but not necessary to do it.

 

[tashasdaddy]

Re: 73 Johnson Seahorse 2 HP help

i would do a decarb after you get it running, will clean out the complete interior.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

afterwards compression.recheck

 

[fishingfrenzy]

Re: 73 Johnson Seahorse 2 HP help

Thanks again for the replies guys. I just got the powerhead back onto the lower unit. My question is, how hard should the prop be to spin by hand? It gives a pretty fair amount of resistance, but everything seems to be doing the right thing. Any thoughts? Thanks again!

 

[fishingfrenzy]

Re: 73 Johnson Seahorse 2 HP help

I took off the lower unit again, and the prop and shaft spin fine like that. It's the piston and in the powerhead that's a bit hard to move, is this normal?

 

[fishingfrenzy]

Re: 73 Johnson Seahorse 2 HP help

Any idea how hard that piston should be to move? It really doesn't get bad before I put the cylinder head back on. Any ideas?

 

[Xcusme]

Re: 73 Johnson Seahorse 2 HP help

Well, it depends on how you're trying to turn the crank shaft. If your using your fingers to spin the bare crank shaft, it could be a bit difficult...depending. You should feel some resistance from the rings on the cylinder walls and a negligible amount from the needle bearings on the crank shaft and rod journals etc. If the plug is installed, you'll feel increased resistance from the compression, and that's normal and what you'd expect! Worse case is rusted bearings or scuffed piston etc. You could pull the exhaust cover and inspect the piston and check for ring movement through the exhaust ports. Pulling the head would allow inspection of the cylinder wall. The crank shaft should be easy to turn, with the flywheel attached and the plug out. If the lower unit is installed, you'll have to add the resistance of the water pump impeller and gear train etc. Pull the plug and give a good shot of oil in the cylinder and turn the flywheel. BTW, if you havn't changed the water pump impeller, do it now and turn the flywheel clockwise only.