P220

[Oak]

Picked up this boat anchor a few weeks back to do a little learning.
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Why not buy a 26 year old engine and see if I can get it running. I drove 80 miles one way to look at it because the CL add looked like it was in good shape but the owner said it had electrical problem and he couldn't get it running. Oh ya, he forgot to tell me he sawed off the pto shaft because it was to long to put in his Case and one of the mounting legs was also cut off.
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All in all, he was a very nice older gentleman and I figured what the heck and loaded it on the truck.

I got it home and started checking it out. The sump was about a 50/50 mixture of gas and oil so I drained that out and removed the carb for a good soaking. To remove the carb you gotta pull the intake manifold off on Onans. I inspected the intake manifold and could see that it needed resealed because when I stuck my flashlight into it I could see light at the seams. I drilled out the rivets and split it in two.
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I cleaned it all up, polished the inside, resealed it with Ultra Black and put it back together with small nuts and bolts.
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That's it for now. Stay tuned for the next episode.

[Berwil]

[R Bedell]

Keep us posted on your progress.

[Leadslingingdaddy]

I have a sump....fyi..

[john hall]

Glad to see Onan's getting a little respect!! Can't wait for the next update.

[1811woody]

Originally Posted by Berwil

LOL
x2 cant wait to see the progress I bought a 2nd m18 to rebuild for a back up engine, I've had it running just to see if its worth messing with buts that's as far as I got. I think its a great idea to tinker someday well be almost as knowledgeable as some of the other guys on here.

[Oak]

Well, I got a little more time to work on the Onan. I didn't try to start because the po said it wouldn't run so I figured I would dig into it.

I pulled the flywheel and found that the keyway was sheared off. The P series have an electronic ignition and the keyway fits into the pickup ring on the crank to keep the timing correct. Problem #1 found. Here is what it should look like.
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To remove the crank you need to remove the gear on it and that requires a special tool that I don't have.
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The Onan rebuild on MTF had a homemade tool so I searched my junk and found something that should work. It was a split taper bushing that are used on sheaves. The center hole is a little big but it worked. I cut the back part of it off and drilled two holes for the (2) 10-32 allen head screws that are screwed into the gear to pull it. I tried my gear puller but I couldn't get a good straight pull on it so I used this puller. It was on there tight but it worked.
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Here is why I'm changing the crank. The po cut it off and also the foot on the oil pan. This plate comes off so the crank can come out. Here is what the main crank bearings look like in an Onan.
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[Oak]

Pulled the heads and this is what they looked like. STD on the pistons, I guess that's a good thing.
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What's up with this? The intake valve seat fell out in the last pic.
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I'm going to take it to a machine shop to see how bad it is. I have another crank that I hope can be used if the block is not scrap.

[bocephus1991]

Hopefully it's salvageable! That piston in third to last pic looks scored to hell! Good luck keep us posted on your progress!