Johnson FD-10 hard to crank

[Fastwin18]

I’ve got myself a nice new winter project. Although cosmetically rough it technically seems ok and all parts are there. The previous owner even replaced one of the intake covers with a newer one in preparation of the newer fuel pump. Impeller seems new as well as all the ignition parts. Compression is 98 for the top and 96 for the bottom cylinder. Top seal is still good. The previous owner clearly spent time and money on this motor but never got around to finishing it.

The only problem is that it is really hard to turn the flywheel. I’ve removed the spark plugs and lower unit but still it turns very difficult. I don’t think I would be able to pull hard enough to get it started. As a comparison, I think it is about twice as difficult to turn the flywheel as my 1960 18 HP and perhaps 3 times more difficult than my 1958 10HP. Somewhere there is just a lot of friction. I’ve removed the intake covers, the pistons look clean and are covered with a thin layer of oil.

From what I can tell it does not look as if the crank case has ever come apart. Does anyone have an idea what could be causing this? Could it be that the piston rings have been replaced by new ones that don’t fit properly?

[crosbyman]

if the cc does not seem to have  come apart  rings should be original .  Could you take ou the carb and back plate  to peek inside the CC to see if  it is all rusted up inside ?

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[necks]

I had problems with mice making a home in and around flywheel and magnets, nesting area getting jammed between coils and magnets. Does flywheel look like it is positioned on crankshaft correctly with key installed. Next, I would pull flywheel off and check if the coil heels are not hitting the magnets on flywheel, then check heels of armature plate to be in the correct position. I’ve had that problem more than once. Gene.

[Fastwin18]

necks wrote:

I had problems with mice making a home in and around flywheel and magnets, nesting area getting jammed between coils and magnets. Does flywheel look like it is positioned on crankshaft correctly with key installed. Next, I would pull flywheel off and check if the coil heels are not hitting the magnets on flywheel, then check heels of armature plate to be in the correct position. I’ve had that problem more than once. Gene.

Gene, the flywheel is already off, it’s absolutely clean under there. No rubbing of the heels.

[Fastwin18]

crosbyman wrote:

if the cc does not seem to have  come apart  rings should be original .  Could you take ou the carb and back plate  to peek inside the CC to see if  it is all rusted up inside ?

Yes, I should have thought of that myself. 😉

[necks]

The compression on both cylinders sounds good to me. Did you have this motor running yet, if not the cylinders are probably dried up from sitting. The next thing I would do, is take spark plugs out, pull starter rope and see if that makes a big difference , if not, squirt a little oil in each cylinder, see if that helps. Do you know if the other owner had crankcase apart? I put motors together and tightened bolts on crankcase covers and had trouble turning crankshaft before I had anything else on crankcase yet. I put a 2×4 on bottom of crank and tapped it with a dead blow hammer, which apparently straighten the crank into the crankcase. If that’s the case you will have to take powerhead off lower unit, may have to reseal cylinder case again,also you will get your chance to see what the rest looks like, that case you will know what you have. It sounds like a lot of work, but will be worth it when you are done.

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Fastwin18

[Fastwin18]

Hi Necks,

Thank you, it just needed a few drops of oil indeed. All good now, I’m sure this will be a runner.

[Fastwin18]

It also increased compression to 103/104 lbs, way more than I anticipated.

[necks]

Apparently the motor has been sitting for awhile, that’s normal for compression to increase when you squirt oil into cylinders. It sounds like you found the problem. Not sure what the gas-oil mix is supposed to be, but find out and make sure you use quality oil and gas. Next I would take lower unit off and check or replace water pump, and make sure all passages are open to check for broken vanes jammed in there, then I would drain oil in lower unit and check for leaks, no more than 10psi, otherwise you could pop the seals. You can submerge lower unit in tub of water, if no leaks, and add oil, it’s ready to go. Then go to ignition and make sure everything is correct, using timing tool. Install motor in test tank, fire up, adjust carb in forward gear, and listen to that sound of a fine tuned engine running. Do you have a Johnson Service Manual for that model, if not, you need to get one, it will answer all your questions about adjusting all that pertains to that engine. I’ve seen some on this site that can be copied. Gene.

[crosbyman]

cheapest and the best book for 20$

https://watercraftmanuals.com/outboard/johnson/manuals/johnson-302231.htm

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