By Todd Simmers on Unrecorded Date: Edit

I bought an older single cylinder Rockwell engine to replace my wore out Kohler engine in my Sierra Trail Boss. The last person that had this engine tried to replace the points, and could never get it running again. After getting the wireing back to the way it should be, I can not find any info any where about gapping the points. Could anyone tell me what the gap should be? I Have good spark, and good compression, but the engine just will not run. It backfire some, but will not run. if I remember right the engine is a 297CC, I think. Thanks.

By ISAAC EISENMAN (Tropicjungleboy) on Unrecorded Date: Edit

HEY TODD: this jlo-rockwell 295 use 0.018 gap on points...you should use a narrow non metalic gap calibrator....also check for grease on poins and "flat" contact between points...did you replace also the condenser???.........also is possible that the coil has failure...you can test it with another 6 volt coil........good luck and fast return to bounce!!!!

By Mark Muranyi on Unrecorded Date: Edit

Todd, I'm going on memory here so take this for what it's worth.Your ignition system is a Bosch.The same on the Kohler. The point gap being .016" nominal. The mechanicl advance must be secured in the fully advanced position while your doing the timing.Also are you aware that a dial indicator must be used at the top of the piston to indicate before to dead center when the points are to just start to open. This would be I think .098" before top dead center. Hope this helps.
Mark

By kush on Unrecorded Date: Edit

Todd,

Go to the nearest library & find a snowmobile repair manual. The have the info you need. I have some bad copies of JLO enigne info out of one of these manauls. I can scan them & send if u need. Let me know.

By johnmaiolo on Unrecorded Date: Edit

Richard has shop manuals for JLO's.

By zerbo on Unrecorded Date: Edit

can sombody tell me where to get a dial indicator for timing. and how much does it cost.

By ISAAC EISENMAN (Tropicjungleboy) on Unrecorded Date: Edit

HEY ZERBO:

with spark plug removed insert a crew driver thru spark plug hole until reach top of piston...move BY HAND cooling fan until reach top piston movement......that's your "0".....mark (make a little notch on crankcase and matching cooling fan when reach ("0") now with a geometry transponder you can rotate BY HAND to LEFT the quantity of grades that you whant to "advance"...when you reach it...make a little notch on crankshaft screw..(after all, if you deside to take out the cooling fan that will be the only reference mark!!!....don't forget to put back BLUE THREAD DRESS to all bolts that you deside to move...otherwise engine vibration will release then soon!!!.........happy timming!!!

By zerbo on Unrecorded Date: Edit

hey isaac thanks for info, but what is a geometry transponder.I did a pretty good job on restoring this 70s max11, but im not so good with the motor. I already seized up one piston with this motor. im rebuilding it and want to make sure i set the timing and points right. read your tip on electronic ignition, sounds like a good improvment,might try that olso.

By ISAAC EISENMAN (Tropicjungleboy) on Unrecorded Date: Edit

HEY ZERBO:

a geometry transponder is a device to calculate degree..has a half circle shape with a mark on center of flat side and "0" to "180" degree mark across the circular edge...therefore a complete circle is equal to 360 degrees....half circle equal to 180 degrees and a quarter 90 degrees..."advance" should goes as 8 degrees before reaching top piston, when turning engine to right when watch cooling fan side......and what mark muranyi mention about the centrifugal advance device ( a spring loaded cam that change when to open the points) it's true!!! you should make this adjustment with full advanced included otherwise you should get overall wrong timming when getting hi rpm.......if you desides to get thru with the cdi don't forget that you should rotate this points and magnetos base 90 degrees to the right

By zerbo on Unrecorded Date: Edit

thanks guys,its starting to sink in.now i need to find a transponder. found a guy close by that hase the parts i need,mabie i can borrow his if he hase one, should be putting it back together next week.

By zerbo on Unrecorded Date: Edit

still havent found a trasponder,any one know where i can get one.

By Al on Unrecorded Date: Edit

Zerbo,
Translations:
Transponder = Protractor.
Grade = Degrees.
Blue Thread Dress = Blue Loctite.

If I missed any, please indicate.

Al

By ISAAC EISENMAN (Tropicjungleboy) on Unrecorded Date: Edit

THANKS AL!!!

By Al on Unrecorded Date: Edit

You're Welcome Isaac!

By Ben Englund on Unrecorded Date: Edit

Anybody know how important the exhaust length is on a JLO 340? I have one that I put a muffler on with 2 ft of 2" flex pipe and I don't seem to be getting the power I should.

By tropicjungleboy on Unrecorded Date: Edit

HEY BEN: about the muffler issue jusust remember that you are working with a TWO CYCLE engine that burns gasoline/oil mixture.......it-s possible that the burned oil soaks the internal silencer atenuator fibres and expand them to a point that now you get clogged your muffler.....two cycle engine at high rmp need a lot of air circulation!!!......if your engine performances great with just the flexible pipe YOU FIND THE PROBLEM!!!!.....please keep us update about this test...........

By Ben Englund on Unrecorded Date: Edit

Well I tried it without the muffler or pipe and the max rpm stayed about the same. I shortened the pipe to the motor and the rpm dropped. I took apart the carb and everything seems fine. Guess I'll try something else?

By liflod (Liflod) on Unrecorded Date: Edit

Clean and gap the points and change the spark plug.