86 Marathon 2 stroke boggs down

[racin161]

Scottyb hangs in the electric and popatop is like horse hockey all over. Don't get offended Popatop just a phrase

[opsled]

Originally Posted by pathfinder

SInce I got no response on this post I'll try to update what I have found and pose some more questons. Can bad engine mounts cause this problem, I think all 3 of mine are shot. the engine moves way left under load. I have adjusted carb and the cart is on jack stands When you open it up the engine shifts left and some times the clutch will fully close and others it won't.

The enigine runs smooth through throttle but near top end it sounds like it's popping back through the carb. I'm just trying to learn what is going on with this cart.

I don't do much work on carts but do a ton on sleds.

I will say that if your clutching isn't right the rest won't matter. A strong running 100hp sled engine will be a lazy pooch with the things going on as you describe. Proper belt length, width and engine alignment is crucial to the operation of the CVT system. Belt to short/narrow and it will ride to low in the secondary at start to give the right low end power. To narrow moves the weights in the primary past where they should be at a given RPM which allows them to have more force to shift up. The system will be shifting up early all the way through and keep RPM down out of the engines power band. If the belt is to short it can bottom in the secondary before it reaches the top in the primary. When this happens the engine is now trying to streatch the belt to achieve full shift. This will completely skunk top end power. If the mounts are bad alighnment and center to center will be moving all the time. No CVT system will perform well like that.

Carts make very little HP in comparison to most sleds so clutching should be even more important to proper performance.

Get your mounts fixed, clutches cleaned and aligned and install the right belt first. Without that being right you could be chasing ghosts forever.

opsled

[pathfinder]

Thanks Opsled for the information. Ordering new mounts friday. What is the procedure for cleaning the primary clutch, I thought these were non servicable? It is a comet clutch and I know that most sleds clutches are servicable but cannot find any information on rebuilding one on a cart.

[opsled]

I just did one on an EZGO with a 102 Comet. They are also used on many sleds so I has quite familiar with them. There are many different makes and styles of CVT clutches but the basics is to remove the clutch, dissassemble, clean and inspect all the components, replace anything that is worn out of spec and reassemble lubing ONLY the points required.

You need to figure out what you have for clutches and get the proper procedure from it's manufacturer. If you google search the subject you will find a lot of information. If I had your cart I'm sure I could figure it out but the service manual for your cart should give you all the info you need including alignment specs. Whenever I'm working on something new to me I want the manual. It saves time and things get done right the first time.

Can you get a manual from wherever you're getting the mounts? That would be best and will help with any other issues you may have now or in the future.

opsled

[pathfinder]

I can get a manual but it dosen't have anything on rebuilding the primary clutch. Dealers say they have to send it in for repair, non servicable but we know better I guess I'll have to do some further investigation and possibly dissassemle it to find out. Just worried about the spring pressure when doing this.

[opsled]

The spring pressure probably is not that much. The one I just did had very little in comparison to what I'm used to. Lower RPM systems usually have a softer spring.

There is a tool to hold the spring while you take it apart. I have one and it's very handy but unless you do a lot of them it isn't worth buying. A threaded rod through the clutch center with nuts and washers large enough to hold it together while the cover bolts are taken out is all you need (if that). Once the cover is loose just back off the nuts on the rod until the spring pressure is gone.

Again if you find out the model of your Comet you will find info on the net on how to service it.

opsled

[racin161]

The primary or DRIVE clutch has very little spring pressure on it when you take the cover off and can be reassembled by hand with no problem. Now the DRIVEN is a different story as that spring is holding the clutch in the closed position and there's quite a bit of pressure on it. I made a tool to compress that one to disassemble and re assemble. With that said there is not many serviceable parts in side the DRIVE clutch. Take it apart (the cover off) and simply clean all moving parts paying attention to the arm pivots and rollers free them up then clean up the shaft the moveable shiv slides on a bit of anti sieze on that shaft and a bit of 30 motor oil on the pivots and arms and your redy to reassemble.

[pathfinder]

Thank guys for your input looks like I've got work to do this weekend I'll update when completed. This forum is great!!!

[pathfinder]

just to update on the cart. replaced the engine mounts and regaind lost power and noise went away. discovered that the old mounts were letting engine shift way left and the driven clutch cover was hitting causing the popping, and the belt was going slack from the engine shift. cart runs smooth now.

[BrewCityMusic]

I just came across this thread and was going to jump in RE the mounts, as I had the exact same issue before I redid mine ... Mine was bad enough that it actually wore completely through the end of the clutch cover where it was rubbing on the motor under load ... Glad you're all fixed up !!!!