|Posted on Sunday, January 31, 2010 - 12:24 am: ||
My buddy ran his vintage snowmobile lean and melted a hole through the piston. It's a 1972 Scorpion Whip made just up the road from here, powered by a Cuyuna/JLO/Rockwell F/C 340. After cleaning the jugs and replacing the pistons, rings, and top end gaskets she should be ready to go. But after getting everything back together, she won't even sputter.
It has fine spark, new plugs, and is getting fuel and air, but nary a puff of smoke can be negotiated from her.
Any ideas? Anyone wanna come pull on her for a while?
|Posted on Sunday, January 31, 2010 - 12:29 am: ||
How long has it been since it last ran? Is the plug/plugs wet or dry? Did the pickup coil/igniter get moved from the correct spot for timing? Is the gas old?
|Posted on Sunday, January 31, 2010 - 12:32 am: ||
Plugs do get wet, timing remains unchanged, gas is new, and the last time it ran was about three weeks ago.
|Posted on Sunday, January 31, 2010 - 12:37 am: ||
D-Maybe put a little oil in the cyl.'s.
Maybe blow a little air pressure in the fuel tank and check the line from the crankcase to the fuel pumps.
Sorry,my shoulder and back are sore from pulling on mine!
|Posted on Sunday, January 31, 2010 - 12:39 am: ||
"Nary a puff" ..........if everything else is correct.......usually means flooded and (or)fouled plugs. A lot of two stroke fouled plugs won't come back to life,even after a good cleaning. Make sure that the pulse port hose on the crank case is dry. If it is wet,it is drawing fuel from a bad fuel pump diaphragm and causing the flooding.
|Posted on Sunday, January 31, 2010 - 05:15 am: ||
I always used to use a little Redex down the bores to get a good seal, smokes like a bastard when it fires though.
May be a stupid question, has it got a reed valve? is it in the right way round?
Go back & check all joints, then try again with a fresh plug;
I have been known to use an airgun with a socket on the crank for turning over 2 strokes. it saves your arm.
|Posted on Sunday, January 31, 2010 - 07:54 am: ||
Fresh plugs, +1; fouled plug sometimes will spark outside cylinder.
Two-cylinder engine. Spark lead-coils to correct cylinders? Timing checked confirmed?
Lower-end, crankcases, can "load-up" with unburnt fuel, re-flooding engine promptly at re-start attempts.
Dry out, ventilate, combustion chambers and lower end before attempting restart.
|Posted on Sunday, January 31, 2010 - 08:58 am: ||
Do they have reed blocks like dirt bikes? Make sure those reed blocks are back in, clean, and all oriented correctly. Also, make sure it is completely fresh gas, I got burned by having older (not that old) gas in the bike after finishing a rebuild. Old gas, nothing. New gas, fired up third kick.
+1 on pulling the plugs and making sure they are clean. Contact cleaner (at wal mart) followed by compressed air (if you have it) is a good way to quickly clean a fouled plug. The 90% plus isopropyl alchohol from the drug store would probably work well also.
Also make sure the piston went in the right direction... yest it matters on a two stroke. The person that sold my the kids non runner KX-60 made that mistake. They don't run that way.
Look for spark as well. Maybe the stator got damaged during the event or on disassembly and reassembly. Check timing as well, if that is off it won't start.
|Posted on Sunday, January 31, 2010 - 09:31 am: ||
I've had very little to do with two-stroke engines in ~40 years, but in my experience they are the most cantankerous things about starting that man has ever invented.
I co-owned a go-kart with my best friend growing up, that was powered by a West Bend two-stroke. Through an immense amount of trial and error I learned a lot. What's said above about spark plugs seemed to be the most important thing. The weirdest thing we found was that you'd run a spark plug for a few days and then the engine would begin to get hard to crank. Swap in a fresh spark plug, and that'd be OK for a few days. Go back to the original spark plug (cleaned or not), and it would be OK for a few more days. Weird.
|Posted on Sunday, January 31, 2010 - 10:23 am: ||
if spark and every thing is in place. check the exhaust. my 250 penton sat all winter and a mouse built a nest in the exhaust.took exhaust to car wash after blowing nest out ran like a champ.