1987 cushman truckster engine rebuild

Paul70

I have been asked to work on the Cushman. it cranks smooth at times and at times it cranks as if the battery is weak even though I have a charger on it set to crank/start position. I have noticed it has oil coming out the blow by tube just from cranking, it also has gas in the oil, I told the owner that the motor will probably need to be rebuilt since the rings and cylinders are probably wore causing the blow by. he told me that when it did run it did have a lot of blow by. my question is if there are engine rebuild manuals for these motors and where I can get kits for them. also if you have information on where I can get the best quality parts for this machine.

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

Paul70

Also could somebody tell me the approx. compression I should get while cranking with both plugs out.

CharleyL

Paul,

Welcome to BGW. Please take the time to go to "User CP" at the top left of this screen and tell us a few details about you and the Cushman, including the town and state where you are located. One of us might be near you and can better help if you should need any hands-on help. Please post a photo of the Cushman when you can. It will help identify it for any future questions.

Did someone over fill the crank case with oil? Incorrect timing will cause pre-detonation and stall the engine during attempts to start it. Gas in the oil most likely means that the diaphram in the mechanical fuel pump is bad and this will raise the level of oil in the crankcase too. The mechanical fuel pumps are hard to find, and expensive when you do find them. For about $60 I bought an electric fuel pump for my Cushman from the local auto parts store. It connects directly between the tank and carburetor and it's pressure is self regulating, so the bypass filter is no longer needed, but it's a good idea to put an inline filter between the electric pump and the tank. These pumps only have 2 electric wires. The red one connects to the ignition switch so it has power whenever the key is on. The black wire connects to the frame. You can remove the mechanical fuel pump and block the hole with a simple to make metal plate and some gasket material. The 2 original bolts will hold this plate in place and keep dirt out of the crankcase.

I have a 1987 Cushman Truckster. Is yours a Truckster or a golf cart? For the motor service manuals this doesn't matter. Both use the OMC 22 hp engine. Go to www.sillylittlecars.com and then select "Manuals". Then click on "Service Manuals" in the text. There are several manuals there in .pdf form that will provide all of the motor information you should need. Download both the 826767 manual and the Supplement. This should be all you need to re-build the motor, except for the parts.

The ignition system consists of a timer (the points part of a distributor and 2 ignition coils that are wired in series with a ballust resistor. Then a spark plug wire is connected from each coil directly to the spark plugs. Both plugs fire every revolution, but one cylinder is on the exhaust stroke, so only the other one which is on compression, fires.

The cylinders of these motors don't seem to wear out much, unless it was run without oil. You most likely will only need new rings and gaskets, but beware, you will need a split band type of ring compressor to get the cylinder back on. The standard round ring compressor for most engines won't work. You can buy a split band ring compressor set from Amazon for about $34. You will only need the 3.5" band and the special pliers, but they aren't available out of the set. I hone my cylinders and use them again if they aren't otherwise damaged. The spark plug threads are usually what goes first and I've had bad luck trying to use inserts to fix them. New cylinders complete with valves and springs are available for $300 each if you should need one. Dennis Carpenter Cushman http://dennis-carpenter.com/stepthrus.aspx can provide the gaskets and cylinders that you should need. They are mostly a Cushman scooter parts provider, but have the OMC engine parts. www.directparts.com is another source for gaskets. They both also sell complete new short blocks for the OMC 22 hp engines (for $1500). Dennis Carpenter is located near me, so I buy from them if I need engine parts. They both have new starters, if you should need one, but I would make certain that the starter solenoid is not the problem first.

Let me know if you need anything else.

Charley

Paul70

It is a Cushman turf truckster. it does appear that the oil is over filled but I don't know how long it has been left unchecked, it could possibly just be that it has so much gas in the oil to cause it to be over full. I am going to drain the oil and replace the fuel pump with an electric pump. is there a certain weight of oil that I should use in it?
by the way it has passed through 2 owners before I got it to work on. the current owner told me that when he first got the Cushman it ran fine but had a lot of blow by. he said that it sat for awhile before he tried to start it again and it cranked slow as if the cylinders were trying to seize up, he was afraid with so much blow by that it had ran low and started trying to lock up. since I have been working on it I have had it crank smooth with the plugs out for the first time I tried turning it over. the next few times it was dragging as if the starter was going bad, but with the information you provided about the solenoid I am wondering that might be where the problem is. I am going to look into it and see if the solenoid needs to be replaced or if maybe the connections are loose or dirty.

CharleyL

The OMC 22 hp motor uses 1 1/2 qts of 30 weight oil and two qts if the filter is changed. Don't over fill it at all. There isn't much leeway here. Put in the 1 1/2 qts and if you changed the filter, start it or turn it over a few times, then check to see how much oil needs to be added. The fluid types and amounts for the transmission and differential are in the spec sheet as well.

I mounted my electric fuel pump on a plate attached to the chassis just below the gear shift. It needs to be nearly level with the outlet tube of the tank. An inline filter between the tank and the fuel pump is a must. I just bought a Fram G2 at the auto parts store. Connect the output of the electric fuel pump directly to the inlet of the carburetor. Don't use the bypass filter that was used with the mechanical fuel pump. If the carburetor is a Keihin, there is a tiny screen filter inside the plastic inlet of the carburetor. While this is a nice idea, they plug up and they aren't available any more. Use needle nose pliers to pull it out before connecting the fuel line.

Have you looked inside the gas tank? They are usually heavily rusted on the bottom and need heavy cleaning or your new fuel system will be ruined quickly. I bought a tank restoration kit that's made by KBS Coatings. I got it through Amazon. It's a 3 step process with a strong detergent that loosens and removes the rust, an etching solution to prepare the metal for the final step, and an epoxy paint type coating that lines the entire inside of the tank and prevents further rusting. It costs about $40, but is very much worth it. My tank is better than new inside after using this kit.

I have had 3 of these engines apart including the one in my Truckster. These other two
had been treated very badly, one looked like it had sat in a mud hole for a few years. None of them had severe wear in the cylinders, but there was pitting at the top end of the cylinders of the mud hole engine, likely from watter getting in through the intake and exhaust. The pistons were all in good shape. All that was changed was the rings and gaskets. The rods, valves, crankshafts, cams, and bearings were all still useable.

I'm almost willing to bet that at most, all you will need to do inside the engine is lightly hone the cylinders and put new rings in the pistons. New cylinder gaskets, intake and exhaust gaskets, and it will be fine, of course after you drain and replace the oil and the filter.

I rebuilt my Keihin carburetor too. The accelerator pump diaphram, float and needle valve were the most important parts to change. Make certain that the passages to the accelerator pump are clear too. I ordered the parts that I wanted to replace from my local forklift service shop/Bobcat dealer. Each part had to bee ordered separately, there was no kit, and it took almost a month for all of the parts to arrive. My motor ran before doing this, but it usually starts in a half revolution now and only needs a little choke when it has sat all night. f you have the Keihin carburetor I posted an exploded diagram and parts list on this forum some time back. A search for "Keihin" and "CharleyL" should bring it up, but if you can't find it I will or I'll re-post it..

There are air flow dampers in the flywheel housing part of the engine that are controlled by temperature sensing bellows assemblied on the bottom of the cylinders. These dampers need to open as the engine warms up. If one or both dampers fail to open the motor will overheat. After fussing with these for 3 months, I gave up and removed the thermal sensor units and bolted the dampers wwide open. My motor now never runs hot. I don't get as much heat out of the manifold heater for the cab heat, but it rarely gets below 25 deg F here anyway. I may wish I hadn't done this when Winter gets here, but I don't think so. Lots of small engines don't have cooling dampers and they run fine in the Winter.

My 1987 Truckster spent 12+ years sitting untouched outside in a forest environment before I bought it. The gas tank had a 1/4" layer of rust in the bottom, spiders and small trees had taken over the cab and the door hinges were rusted shut. All of the tires were rotten and three were flat and in mud almost up to the axles. The left rear brake drum was rusted to the shoes and the entire brake system was full of rust. For more details and probably some interesting reading about it go to this link http://www.buggiesgonewild.com/gas-g...ed-forest.html. When they sit outside in the weather or suffer from a lack of maintenance they need a lot, but they can be saved, and they are worth the hard work of saving them. Once everything is fixed, they are very reliable little vehicles again.

Keep me posted as you dig deeper and I'll try to point out more details and things to watch for. If you want to phone or e-mail me for quicker help, send me a PM (private message) on this forum with your contact information (phone, e-mail, etc) and I'll reply with the same.

Charley

CharleyL

Paul,

You have been too quiet. Are you making any progress with your Cushman motor?

Charley

Phillip27

I just bought a 1990 Cushman Truckster and seem to be having the exact same issue as this! Seems fuel is raising my oil level ect. Great read and thanks for the info.

Phillip27

Would love to locate someone who has experience working on these in NC!

Phillip27

Hey Charley, could you post a pic of the dampeners bolted open? My dampeners are apparently completely disconnected (springs and rods) and after I dig through several inched of muck to get to them I want to be sure they are open!

CharleyL

Phillip27,

I sent you a PM. Look for a link to it in the upper right of the BGY screen near to your name and under "Notifications".

Charley