1981 marathon trouble accelerating. High Altitude

[puzomatc]

New owner of 1981 Marathon. Sexy on top of powerful i'm sure
I live in Lake Tahoe, elevation 6200'+
I'm told i need a high altitude jet for the carburetor.

Right now it has no pick up and no top end. The factory exhaust was rusted out and was replaced with flex tubing and a motorcycle muffler.

1)I was told that the current exhaust was letting to much exhaust gas through and would not have much top end without a little back pressure. the factory muffler looks like about a 1 1/4" in (from the exhaust port) down to a 3/8 at the end of the muffler.
Should i put a metal plate between the engine and the new muffler with a hole drilled in it to create some back pressure?

2) carburetor rebuild kits anyone? 1981 2 cycle. can't find 'em. help.

3) high altitude jet? the book says i should use a number 80 for my elevation. I talked to an ezgo distributor and no one sells the 80 jet. help? i was also told a jet is a jet is a jet. so a number 80 holly jet from a mustang would work. any comments?

4) the belt i have is missing a couple teeth and is loose. i was told not to replace it because the clutch would keep going out and out untill it grabbed, so missing a couple teeth wouldn't matter. it's also very loose. i can take it off without stretching it at all. replacement?

5) is there any way to clean the factory gas guage? its clouded over from the inside.

6) oil to gas should be between 70:1 and 100:1 (gas to oil rather) right?

Thanks

[ruredy]

Welcome Puzomatc

Originally Posted by puzomatc

New owner of 1981 Marathon. Sexy on top of powerful i'm sure
Lets see, that's 28 in human years.... 196 in cart years..... yea, it's still on top of its game... wait, that might of been dog years....
I live in Lake Tahoe, elevation 6200'+
I'm told i need a high altitude jet for the carburetor.

Right now it has no pick up and no top end. The factory exhaust was rusted out and was replaced with flex tubing and a motorcycle muffler.

1)I was told that the current exhaust was letting to much exhaust gas through and would not have much top end without a little back pressure. the factory muffler looks like about a 1 1/4" in (from the exhaust port) down to a 3/8 at the end of the muffler.
Should i put a metal plate between the engine and the new muffler with a hole drilled in it to create some back pressure?
No, you should put the right muffler on it, or as close as you can get. It needs an expansion chamber, the engine's fuel intake cycle depends on having the correct muffler

2) carburetor rebuild kits anyone? 1981 2 cycle. can't find 'em. help.
Not availible, new carbs are or maybe rig one off a 250cc dirtbike on it
3) high altitude jet? the book says i should use a number 80 for my elevation. I talked to an ezgo distributor and no one sells the 80 jet. help? i was also told a jet is a jet is a jet. so a number 80 holly jet from a mustang would work. any comments?
Mustang parts, maybe, you could always try drilling it out some but if the carbs wore out, what's the point
4) the belt i have is missing a couple teeth and is loose. i was told not to replace it because the clutch would keep going out and out untill it grabbed, so missing a couple teeth wouldn't matter. it's also very loose. i can take it off without stretching it at all. replacement?
Wow, I can't even explain how much I don't understard this. Sounds like you need a new belt

5) is there any way to clean the factory gas guage? its clouded over from the inside.
Not that I know of, buying a new one will fix the problem
6) oil to gas should be between 70:1 and 100:1 (gas to oil rather) right?
Sure, that sounds good
Thanks

[puzomatc]

is there a perferred web retailer we go to?
i need a new muffler
the one now isnt' there at all. its gas flex hose tied into a motorcycle muffler

[ruredy]

Up in the header you'll see a selection "Site Sponsors" They're all top notch businesses, if they weren't, we wouldn't let them be here.

[puzomatc]

Update:
I replaced the belt. it's about half an inch wider than the one on it when i got it. Barely any slack on it. Picks up and grabs like a champ. worth the money.
I found a carb rebuild kit and did my thing. I found a Jet at the bottom of the float bowl bolt. This is a sea level jet and it looks fimilar enough to go to the snowmobile shop and ask if they have a different one.

A funny thing happend on the way down the hill. I had my lady follow me in her car to clock me. something whirred and then clicked and bam!, 21MPH!!!!! I talked to a mechanic, he is thinking the clutch finally engaged out all the way. Its' been sitting for a while and the clutch probably needs to be cleaned, right?
I was only going 7 up the hill and 10 on the level ground.

clutch kits? recommended cleaners?