1988 Marathon Problems!!!!

[rfincher86]

I have been having major problems with my Marathon ever since I bought the thing. It did not run when I first got it and after getting it running it blew a head gasket. I got it running again by replacing the head gasket but it would run real good for about 15-20 minutes and then after that it would not start back, it never dies while driving but if you stop it will not start back. I notice when this happens no matter how long I turn the engine over the spark plug is always dry and if I pour a little gas in the cylinder it will fire right up and run good until you stop again. I gave up on the thing for about a month and finally decided to start messing with it again and the first thing I did was weld up a huge hole that was in the muffler and after that the thing ran great for about 3 days and now it is back to acting the same way. I have tried spraying starter fluid on the crank seals when it would not start but that made no difference, I have checked spark and I do have spark but it is not a blue spark it is kind of red, I have gone through the carburetor several times and cleaned it and made sure the float is not sticking. It does have a bad fuel pump but as a temporary solution I mounted a gas tank on the back and just use gravity to feed the gas, I made sure the fuel pump is sealed off. Is there anyway the carburetor not having pressure on it from the fuel pump could cause this? Does anyone else have any ideas as of what may be the issue? I do plan on rebuilding the engine some time this summer because I do have slight play in the crankshaft but funds are tight right now and I would like to get this thing running for now so we can have a bit of fun out of it before I do the rebuild.

[1989Marathon]

Originally Posted by rfincher86

I have tried spraying starter fluid on the crank seals when it would not start but that made no difference

Try spraying them when the motor is running.

[rfincher86]

Getting this thing running is easier said than done but I will try it as soon as I get a chance. It usually starts pretty well after sitting overnight so I may try that tomorrow.

[1989Marathon]

That is a classic symptom of bad crank seals. Do you have end-play or side-play in the crank? Side-play(up/down) will definately take out the seals.

[rfincher86]

It has side play. Its not a huge amount of play but definitely has some play.

[1989Marathon]

Side-play will eventually lead to worn seals. They are cheap, and easy to change.

[rfincher86]

I guess if it is the crank seals that could explain why the fuel pump doesn't work? How long do you think the side play will take to wear out new seals?

[1989Marathon]

You could probably run it all summer, then do a rebuild next winter. The seals are about $9 each. If you replace them, lube them up when you install them onto the crank. If they are dry, they will get smoked immediately.