My 87 Marathon project

cart around

After three months of membership, I’m finally going to make my first post. It’s going to be long. Hopefully it will be informative, and at the very least, entertaining. I want to thank everybody for unknowingly helping me.
Earlier in the Summer, my neighbor picked up an 87 Marathon for 300 bucks. It had faded white house paint, and smoked like crazy. I could see that it was running really rich, but didn’t know why. He kept a supply of spark plugs to keep it running. He lost interest when he traded a month’s worth of grass cutting for an electric Club Car that was like brand new.

I paid him his $300, and made it my own project. I could see a wet plug, and convinced myself that it was an ignition problem. Doing some searching I came across this website, and started reading everything. It seemed like my cart had every symptom ever mentioned here. It ran better backwards, it had intermittent spark, it used tons of gas. The list goes on. The first thing I did was the HEI conversion, and then cleaned or replaced every single electrical contact. I think it got worse. At one point I drove over to the neighbor’s to show off my new headlights. When trying to go home, it wouldn’t even turn over. There was just a loud electrical hum. I pulled the starter to check the brushes. They were good. I jumped the battery straight to the starter, and it turned over. I ordered a new solenoid from Amazon. I then had time to sleep on it while waiting. That’s when I thought that it wasn’t really the right way to check the solenoid. Sure enough, it was corrosion on the positive battery connection. I disturbed it while hooking up the new lights. By a stroke of luck, the new solenoid never showed up. Amazon said they couldn’t find my address for delivery, and refunded my money. Weird, since they deliver here all the time.

In the mean time, I sanded off the house paint, did a quick bondo job on some dents, and then painted the cart. We have a special cabinet at work where we put expired shelf life chemicals. We use those chemicals for personal projects because they are still good, it’s just illegal to use them on aircraft. I managed to find some fuel proof epoxy primer, and a 4 part epoxy red topcoat that just happens to be an exact match to our red stripe down the side of the airplanes. $1200 per gallon for the red, and we end up throwing it away because of the shelf life. The paint turned out so well that I wish I would have done a better job on the body work.

After more reading on this website I turned my attention to the carburetor. I tore it apart, cleaned it, and adjusted it several times. I can have it off in less than a minute flat now. The cart still kept running worse.

Fuel pumped out of the open lines really strong, so I was ready to buy a new carb. It was using so much fuel that I started looking for leaks. The bottom of the gas tank had a hairline crack. Another trip back to the shelf life cabinet, and I scored some AC240 B½ integral fuel tank sealer for jets. That stuff goes for a hundred bucks a quart. After a good coating of sealer, the tank doesn’t drain itself anymore.

I was still thinking about a new carb, and decided it was time for some real troubleshooting before wasting any more money. A compression test revealed 90 PSI cold. I bit the bullet, and yanked the engine. I was surprised to see how good the cylinder and piston looked. There was absolutely no slop. I did all kinds of spraying, and cleaning. It was frustrating not seeing any obvious problems, though the front seal was questionable. I decided to clean the fuel pump while everything was apart. That’s when the flood gates of joy opened up. The bottom diaphragm was ripped, and everything made perfect sense. The plug was always wet because gas was being sucked directly into the crankcase. I ordered a new fuel pump, gaskets, and seals. While waiting for them, I took the head and a 12 pack of caffeine free Pepsi to the machine shop at work. By the end of the shift the broken screws in the head were out, and they milled it .015” for me.

A few days later everything was back together, and in the cart. It fired up, and ran great. I stopped a few times thinking that the clutch was loose because of a weird wobbling sound. It was fine. It ran good for 3 days, and then suddenly seized. CRAP!!. I yanked the engine, and had it completely apart in less than an hour. Frustration can do that for you. All of the cleaning I did must have knocked something loose in the bottom end. The front bearing cage failed, and pushed the bearing against the crankshaft lobe. That’s why it just quit turning. The 2 rear bearings were easy to press off. The front one took some more work because there was no room to get under it. A quality bearing puller at work finally made progress. A good scrubbing in the varsol tank got all of the pieces out, and it was time for new bearings, and another set of seals. I used green Loctite 609 on the seals, and more AC 240 on the case halves. Back into the cart, and all of the connections were made, and we are ready to try again. She fires up, and runs strong. A few trips down the driveway there is a loud backfire and it quits running again. I noticed that it isn’t pumping any fuel, so I knew exactly what happened. I could see that the rear seal was good, so the engine was coming out for the 3rd time.

I’m getting really good at this. 15 minutes later the engine is out, and on the bench. I removed the flywheel, and could see the seal flopping on the shaft. Another coating of Loctite 609, and I staked the seal this time too. After this installation I made double sure that the spring on the throttle cable was pushing really tight on the butterfly. I don’t want any more backfires. It’s been 2 weeks now. I have used it to pull a 5x10 trailer loaded with firewood, and have driven the wife around the pond a lot. The GPS says 17mph on a slight downhill, and 15 on the flats. She wants a seatbelt. I tell her that she can’t have one without a roll bar. Maybe that will be the next project. Hopefully photos will attach.

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BGW

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apaladin

Great Post! Thanks for the detail!

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The wife has MS, so the main purpose of the cart is to let her go for the mail, ride around the pond, and visit the neighbors. Every once in a while I work it too.

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trig123

Great post . I do understand it is an old post but still nice read. I am helping a friend on a cart the same year as yours. I only got 90 pounds of compression on his.
Did you check yours after you rebuilt it and if so what did you get? Thanks and again thanks for the info you posted. Tom.

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I never did recheck the compression. I didn't mess with the Piston or rings. I did have that lip on the head milled down. That post was 5 years ago. I still drive the crap out of it too. I pull trees and a fully loaded trailer. It climbs hills like a goat with 2 of us riding. A new driven clutch is my only major repair since then. I also replaced the rear bumper with angle iron and a 2" receiver. Cosmetically, I replaced the cowl with a 91, and installed a roof. I abuse that cart every day, and really enjoy it.

Dabble Inn

Hi again CA, I'm glad trig123 bumped this post of yours as I've never seen it before. A very informative and enjoyable read, Maybe when you get time you could post up an updated pic? I'm curious on what the diff is on the front cowl between an 87 and 91, I've often thought about putting one on my 85 just to install the built-in headlights (if that's even possible)......

Anyway, Thanks for all you do on here

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You can see that I made all of the mistakes that a new person would make. My biggest mistake was not asking for help.

I went through a lot of trial, and error that increased my knowledge of the cart. At least that lets me help other people. I'm not sure exactly when I found the manual, but I keep it handy for other people now.


The original 87 cowl is an all steel wedge. The 91 is a clipped wedge with the plastic nose. I installed front knobby tires to help steering in the snow. On a down hill left turn, they would rub. The new cowl fixed that problem. My lights are cheap LEDs from Amazon. They are mounted under the roof. They are also unbelievably bright.
I beat the cart, so I don't spend a lot of unnecessary money on it. I'll save that for a new cart.

I do keep telling the wife that I'm getting her a new 48 volt cart to tool around in while I'm sleeping.

Dabble Inn

Oooops my mistake, I was thinking 87's had the clipped wedge with plastic cowl. They must have started that in 88 then, Guess I'd have to trim the front of my 85 to install a plastic cowl. Well, that ain't happening at this point LOL. I'll keep the tiny but very bright little bullet lights I installed at the windshield frame bolts, Thanks

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