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Old 08-24-2009, 10:23 AM
Dsl Lover Dsl Lover is offline
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Default Repair or replace clutch?

Newbie to the kart world here. I bought a used (well used) manco single seater with a dead axle and a 3hp B&S that only has 60 psi of compression.

After much cleaning, I got it running - but Whenever I would pull the pullstart (even without the engine firing), the clutch (12t with a spring visible through the holes) would engage and start the wheel spinning and pull the cart forward a little. It wasn't engaged all of the time - I could roll the cart and it would not turn the engine over...

Judging from the age & condition of the engine, I'm going to buy a new Greyhound (Clone) 6.5hp ($119.99 brand new) to put on there instead of rebuilding the 3 horse.

My question is - can the clutch be cleaned and reused? Do they go bad? Or am I better off buying a new one?
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Old 08-24-2009, 10:37 AM
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Quote:
Originally Posted by Dsl Lover View Post
Newbie to the kart world here. I bought a used (well used) manco single seater with a dead axle and a 3hp B&S that only has 60 psi of compression.
Most small engines have a compression release built into them for easier starting so using a compression gauge tells you almost nothing about the internal condition of the engine, that 3hp might be fine. I would take the clutch apart and clean it up and lube the bushing and give it a try, I've see clutches act just the way you describe and all they needed was a little maintenance
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Old 08-24-2009, 12:43 PM
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Maybe I should have also noted that large amounts of oil were depositing on the top of the cylinder walls, on top of the piston and on the spark plug. In order for it to fire/start, I have to hold the throttle butterfly wide open (With the choke off). This will allow it to stay running, but it does not accelerate beyond maybe 1000-1500 rpm (It did backfire a few times). If I let go, it sputters and dies. I kept it running in this manner for 2-3 minutes, I then pulled the spark plug to find it very wet (oil I assume as it did not smell like gas). Strange thing is, as it is running, you can see only a hint of black smoke from time to time.

The carb diaphragm is not ripped and the spring and washer are in place. Does this sound like anything typical?

As far as the clutch, what should I lubricate it with?
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Old 08-24-2009, 03:20 PM
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you may have lost your oil rings, or your valve guides could be worn. rings are pretty cheap, guides? idk. if it does have the decompressor, i think i heard they are supposed to read around there. when you have the piston at bdc, how much room is there between the cylinder wall and the piston edge? if it's opened up, bore job is like $50. new piston and rings, idk.but at that point you would be better off with a new motor. money wise. as far as the clutch, if you have the butterlfy full open, the clutch should engage. being that you have to full throttle it to get it to crank all of your rings are likely worn.
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Old 08-24-2009, 08:34 PM
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Black smoke always indicates a very rich condition.
Rings will not solve the problem and don't buy a new engine just yet.
Lean up the carb or check for faulty/clogged air filter.
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Old 08-24-2009, 09:29 PM
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Does your clutch have a name on it?

If you can't get that clutch working, I have one lightly used clutch and one not used at all clutch for reasonable prices.
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Old 08-24-2009, 11:03 PM
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id do a little tune up before anything. try running it with the air filter off. tighten up the fuel/air screw then back it out a 1.5 turns. thats about "stock/reset" from there you can tinker with it. but mike is proabably right, the rings could be bad. make sure you put the spring in, then the washer into the diaphram..make sure thats correct or its gonna be screwed up.
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Old 08-25-2009, 07:34 AM
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Quote:
Originally Posted by vandancouver View Post
id do a little tune up before anything. try running it with the air filter off. tighten up the fuel/air screw then back it out a 1.5 turns. thats about "stock/reset" from there you can tinker with it. but mike is proabably right, the rings could be bad. make sure you put the spring in, then the washer into the diaphram..make sure thats correct or its gonna be screwed up.
When I fired it up, it was with the air filter assembly off (It was VERY dirty), fresh gas, freshly cleaned carb and a new spark plug. I did adjust the fuel/air screw to 1.5 turns from lightly seated like I had read on another post before attempting to start it the first time.

I will have to look more closely at the clutch - I did not notice a name, but also did not examine it really closely.

Thank you for the tip on the diapragm - that was the way it came out, so that was the way it went back in - with the washer toward material.

My main thought on buying a new one - rings $15, bore job $50, Gasket kit $15 - then I still should really get a new gas tank (Was very rusted - now is fairly clean, but just pitted) and a carb rebuild kit $12 and that still doesn't cover any Seals that might be leaking (Oil & dirt mixture covering the output side, and underside of the engine).

Add up what I have listed = $92 + my time to rebuild a 3 horse - which might be too small for the kids to take through the yard (I live on a 55mph country road - so street driving is out).
New 6.5 horse clone = $119.99.

I'm thinking I might clean up the 3 horse some more and sell her.
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Old 08-25-2009, 07:46 AM
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60psi is the lowest psi reading that is considered acceptable, 100psi would be better. I do not know if this will work on your engine, but on my motorcycles engines without any compression release, there are 2 ways to check psi. You should check compression with the engine hot (not so hot that you can't remove the plug, but hot).

1. Dry test: Do a compression test, write down the psi. If it is a low reading goto step 2. If it is ok, then nothing left to do.

2. Wet test: remove the plug attachment and pour in about a teaspoon of motor oil. Do the compression test again, write down the psi. If you get a higher psi reading, then your rings are worn (the oil acts as a temporary seal). If there is no change, then your valves are leaking.

There is another type of test called a "leak down" test. It measures how long compression is held. Those testers are expensive.

http://www.bikebandit.com/product/1654



Check cylinder leakage in 4-stroke engine. Can pressurize the cylinder w/ 60 psi w/ one 70-160 psi air source. Gauge will register leakage past rings, head gasket, intake & exhaust valves. Kit includes 10, 12 & 14mm spark plug adapters, regulator & gauge.
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Old 08-25-2009, 10:10 AM
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There is also a 20% off coupon for harbor freight that would get the engine down to $96, I'm sure someone will want that Briggs though. If your clutch was overheated bad it's possible that ruined the springs so they aren't holding the shoes in at idle. If cleaning and lubrication doesn't fix it I'd get a new one, I'm not sure what you're supposed to use to lubricate it, I just use motor oil on the bushing.
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