cockshutt 540 backfiring

Mike_47 · Apr 30, 2019

Hi just got a cockshutt 540

drove it home about 3km seemed to be running fine except it keep searching for idel up and down revs.

went to change oil later had sludge in oil pan so removed it and cleaned it
Then it sat all winter

Went to start it this year now it won't run without battery, had to clean gas take sediment boul was orange from rust in tank.

Now it will start and idel ok but when under load it backfires seems to run better with chock opened.

So where should I start cleaning the carb?

mach12 · Apr 30, 2019

As far as your fuel system goes, if the tank is rusty you need to start there. Any attempt to clean the carburetor will be undone as soon as you fill it up with dirty gas. I suggest cleaning the tank, making sure you have good flow through the line, then looking into the carb.

Also, be sure to check for good hot spark at the plugs. If your points are bad you won?t get it to run well by addressing fuel alone.

It wouldn?t hurt to check compression while you?re at it to rule out a mechanical problem.

Mike_47 · May 1, 2019

Thanks for the suggestions, yeah I don't know how I forgot to mention I cleaned the fuel tank and sediment bowl.

CraigB. · May 1, 2019

If the 540 ran before storage but now backfires, I suggest you may have spark jumping from one terminal to another in your distributor cap. Time for a tune-up. You may want to change the rotor and wires. Also check the timing. I'm surprised you said it would previously run without a battery. Unless someone put a magneto in it, ignition systems rely on a battery for spark.

Mike_47 · May 1, 2019

I did not word it correctly, I had charged up the 6v battery when I drove it home now that battery won't hold a charge so when I boosted it then unhooked the 12v battery after boosting it died. What I meant to say is do they need the battery to run, which you have answered thanks. Will using a 12v battery on a 12v system damage anything.

550Doug · May 1, 2019

(quoted from post at 18:06:58 05/01/19) I did not word it correctly, I had charged up the 6v battery when I drove it home now that battery won't hold a charge so when I boosted it then unhooked the 12v battery after boosting it died. What I meant to say is do they need the battery to run, which you have answered thanks. Will using a 12v battery on a 12v system damage anything.

I think you may have meant to ask if a 12v battery will damage a 6v system. Yes damage can be done as you need the proper voltage from the coil.
I had a similar problem on a 540 and after throwing a bunch of parts at it, I finally discovered that the rotor shaft was wobbling about too much and was not giving proper spark at the proper time. The bushing on the rotor shaft had too much wear. It worked fine once that was replaced.

cockshutt 540 backfiring

Mike_47

New User

mach12

Member

Mike_47

New User

CraigB.

Member

Mike_47

New User

550Doug

Member

Similar threads