Update: '74 300 timing.. again

[Waterboy7]

Just pulled the 300 back into the garage, she started to back fire last weekend. I pulled the flywheel and the timing hasn't moved since the last time I had the flywheel off and the breaker gaps are good so I'm kind of confused if its timing or carburetion. But for now, I'm waiting for my TDC timing micrometer to arrive and then I I can really make sure the timing is dead-nuts on.

[Steven Rempel]

Engine Kicks Back and Backfires
Spark plug wires reversed.
Flywheel key sheared.
Condenser faulty.
Ignition out of time.
Spark advance mechanism malfunctioning.

these are the things I would look at also. Do you have a service manual as this was listed in there.

I am at the point now with two of mine that the points need to be replaced. everything else is good as far as I can tell so I am left with this in the process of elimination. for me

[Waterboy7]

Yup. I had the points & coils replaced last winter and timed dead on from a buddy and it ran awesome... But then I discovered the engine was leaking some black, greasy, unburnt gas by the timing plate this summer so I replaced the seals. I marked the plate with a chisel before I took it off, and put it back all the same and she ran great when I was done replacing the seals. Then last weekend it out of the blue started to back fire. There is a lot of unburnt gas being spit out the cracks of the exhaust so I am starting to think its the carburetor feeding too much fuel, along with timing.

[Waterboy7]

This is when I replaced the seals..

[Steven Rempel]

What fuel ratio are you using? I find that 40 to 1 will leave a black tar like stuff find it way out and not so much at 50 to 1.

[Waterboy7]

I mix 50:1 even the engine tag says 40:1 with LEADED fuel lol

[robtan88]

Waterboy7. Just for poops and giggles, have you tryed another set of spark plugs? I have seen a rash of bad NGK plugs over the last little while with small engine equipment acting just as you have described. Might be worth trying before you rip and reck. Also if you can read the spark plugs or shine a pen light down the cylinders at TDC and have a look at the tops of the pistons for signs of a detination issues. Many years ago my old 300 use to love getting a whole burnt in the top of the piston because of detination issue. Condensor failing can also do this. Hope this helps...Rob.

[JDT]

I'm going with a bad condensor or bad solider joint on said condensor.

[Waterboy7]

New points and condensers last February, I'll have to look at my plugs! When I last pulled them out, they had nice color and didn't have any deposits or build up. I'll look down the cylinders once I pull the sled back into the shop to time it. Thanks guys for the help, I'll keep you updated!

[Waterboy7]

And yes, steven, I do have a service manual!

[Steven Rempel]

sorry I did not mean any offence. Only trying to help. LOL(help)LOL

I am curious what type of TDC indicator you got/getting, post a pic when you can, I am planing to get a All in one type but not sure which one yet. reviews are always good.


New points and condensers where did you get them and do you have partnumber, I know new breed sells points but condensers are not listed for the kohler motors and want to get the right ones. I am not always the best at online searches and come up with a few results but part numbers are differ

[robtan88]

waterboy7. New points and condensor in February ...Yes... but defective condensor...possibly.!! I have a little story to tell you guys. Not so long ago saw an old 314 lawn tractor that for 3 weeks in a row would come into the shop miss firing, farting, popping, if you could even get it to run at all. Point setting right bang on and brand new. Changed the condensor and ran like a swiss watch again. (for now). Wek later in comes this unit again with the same issue.This happened 3 times and got in touch with DTAC. There suggestion was to install two condensors on this unit. That is what we did, and haven,t had an issue since. So something was changed in the construction or supplier of these "GENUINE kOHLER" John Deere supplied condensors. Not saying this is your problem, but suggesting not to rule it out...Rob.

[Waterboy7]

None taken Steven! And I'll figure out more once my TDC guage indicator arrives, hopefully this week. I bought a central tools brand from auto world or some website like that for $54.

[Waterboy7]

And thanks Rob, I'll definitely keep that in mind!

[Waterboy7]

Well boys, I finally got a chance to pull the 300 back into the shop after finishing the liquifire project, and I found the the verdict on the back firing and missing... The spark plug was bad in one cylinder.
I found out after I installed some stainless band clamps on the exhaust and wanted to see if it would fire after sitting for a month or so. It would pop off and I kept it running while feathering the throttle, while I also felt the manifold and realized one cylinder was cold. :/ so then I shut her off, pulled the plugs a pulled the engine over a couple of times. One spark plug wouldn't even arch through the gap, just go around the outside of the plug. BINGO! Changed the plugs and now I'm ready to ride!