TECUMSEH OHH55 COMPRESSION HELP !

[Poweturn]

Hey all,

I have just bought an off road buggy powered by 2 x TECUMSEH OHH55 69015E (TTP195U1G1RA) Powersport engines. I am having problems with one engine not firing. There is a good spark and fuel is getting through.

I have just done a compression test and after a good few pulls im getting 50 - 55 PSI on the gauge.

Is the compression too low for the engine to start ?

Many thanks in advance

Mark

[motorhead64]

50 psi is low for your engine. I would make sure your valves are sealing properly. Check your valve lash. Squirt some oil in the spark hole and try again. Rings could be warn down as well. MH

[Poweturn]

50 psi is low for your engine. I would make sure your valves are sealing properly. Check your valve lash. Squirt some oil in the spark hole and try again. Rings could be warn down as well. MH

Hi MH,

Adjusted valve lash both to .004 as specified.

Would new rings be enough to help the situation if the barrel and piston are in good condition ?

Thanks

Mark

[Deere2me]

Rings might help, if that's the problem. Could be a sticking or burnt valve. I would do a leakdown test before ya tear into it, it will give ya a good idea of whats wrong.
Manuals are avail at the old forum here: http://www.perr.com/phpBB3/viewtopic.php?f=15&t=8003

[motorhead64]

Could also be a head gasket leak. See if your head bolts are all tight and that your plug is tight in its hole. Look for signs of carbon tracks along the edge of the head. A leakdown will tell you a lot if you have access to the equipment. MH

[Deere2me]

Could also be a head gasket leak. See if your head bolts are all tight and that your plug is tight in its hole. Look for signs of carbon tracks along the edge of the head. A leakdown will tell you a lot if you have access to the equipment. MH

You can easily do a simple "leakdown" test, just use a rubber tipped blowgun (or something to form seal) in the plughole. Remove the air filter, choke & throttle open, remove dipstick/oil fill. Make sure the piston is on compression TDC ( or a little past it ). Lock the crank in this position ( you figure it out) . And GENTLY apply a low dose of air. You'll be able to hear where the air is escaping.Obviously, you don't wanna use full pressure! Could hurt ya! I sometimes rotate it thru, using a breaker bar on the crank nut, as sometimes the cyl can be worn in different spots.
I used to use the QD hose from my compression tester along with a small air regulator for control. I have a good leakdown tester, but I still use the above method more often than not.

[creia]

Mark,
Specifically what do you mean by "fuel is getting through?"
Michael

[grunt]

Just curious, what is the compression reading on the other engine that runs ?

[Deere2me]

Just curious, what is the compression reading on the other engine that runs ?

Good point! Ya also wanna make sure the choke and throttle are completely open.

[Poweturn]

Hi guys,

Thanks for the imput its much appricated.

Just curious, what is the compression reading on the other engine that runs ?

Compression reading is 75 - 80 PSI on the other engine.

Mark,
Specifically what do you mean by "fuel is getting through?"
Michael

Hi Michael, I stripped and cleaned the carb, I also put a few drops directly into the cylinder via the spark plug hole and the engine didn’t fire so no probs on the fuel side.