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Old 07-08-2014, 07:57   #1
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Join Date: Aug 2014
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Yanmar YSM8

I have for sale a 1980 Yanmar YSM8 motor. This motor was an original in a 1980 AMF Paceship PY26. It has been professionally worked on once and I have that paperwork as well as all original manuals and a service manual. The motor ran perfectly from Minneapolis (June, 2014) to Tennessee (October 2014) before wear on the main thrust bearing (flywheel side) started to allow transmission fluid and motor oil to mix as the seal was wearing too. Upon inspection the bearing wear was scoring the crankshaft. Because of the design of a one-cylinder 8HP motor the thrust bearing takes a load every power thrust of the motor. Eventually these become out of round and destroy the seal behind the bearing causing oils to mix.

After removal the crankshaft was taken to a professional machine shop and it was polished with the damage repaired and the crankshaft meeting the wear specifications provided in the service manual.

I have re-installed the crankshaft, cleaned the crankcase and spray lubricated all areas to avoid any rust. Because rebuilding motors would be suspect to knowing whether the mechanic was good, I am going to sell this motor as is with the transmission. I DID NOT TORQUE OR USE ANY THREAD LOCK ON ANY PARTS TO ENSURE YOU CAN REMOVE AND REPLACE DOWN TO THE REMOVAL OF THE CRANKSHAFT. Really, this is better than a used engine as you never know what you get.

The motor must have the thrust bearing replaced, which is a $350 part still available. Had the crankshaft been determined un-repairable, I would be parting this motor out. If I was to rebuild this I would also replace the connecting rod bearing (It was plasti-gauged and within spec) and the timing gear end bearing simply because the crank is out. The connecting rod bearing is in spec, but the timing gear bearing shows wear. The timing gear cover gasket could also be replaced or resealed. These are much cheaper and still available. I assume anyone that buys this will want to go back in and rebuild the motor under their own supervision and authority. This sale also includes a new transmission gasket and the seal for behind the thrust bearing (104200-02220).

The motor has great compression, and had the water pump replaced before leaving Minneapolis. A complete travel kit is also provided including a new water pump impeller, gaskets, fuel filters, washers and belts. Motor mounts are included.

4 fuel filters (104500-55710)
Fuel pump gasket (101720-41820)
Drain plug gasket (123210-09310)
Gasket (104211-????)
Cover screws (26113-04-102)
Fuel filter O-ring (26361-000660)
Drain cooper washers (23616-12000)
O-rings (102103-5520)
Drain plug washers (23626-08000)
Water pump impeller (104211-42071)
Zinc Anode (104211-41388)
V-Belt (104211-42780) - Alternator
V-Belt (104211-42780) -- water pump
Bonnet Gasket -- 104200-11310)

The motor has electric start and that is working fine as is the generator. Controls are included. They can be sent easily via UPS.

I am willing to meet someone to deliver this motor within a reasonable distance. It could be shipped, but the buyer must conduct those arrangements. I will bolt it to a pallet and wrap it if you make arrangements to ship via a carrier. My willingness to drive would be based on a .50/mile cost. I am willing to negotiate this, but a truck is required to haul it. I will keep it split into the motor, transmission and flywheel to make it light enough to lift if I meet to deliver.

This is a great project motor that is worthy of the effort. I have complete faith the motor is good and in working condition even as it motored to the dock for repairs in October 2014. The marina was not capable of fixing the motor and thought the crank was damage beyond repair so it sat in their shop until June 2015. Their crankshaft diagnoses was incorrect, but not known until the motor was removed and the crank taken out. An outboard was fitted to the boat and I brought the motor home to Missouri.

The motor is sold as is with no warranty. One has a choice of a complete rebuild or simply replacing the parts mentioned for many hours of motoring. I would estimate possibly $1000 to make this a like new rebuild of which $350 is the thrust bearing or just replace the thrust bearing and starting it up.
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