16.5 single cylinder popping and missing greatly

[mr.farmall]

Check for air leaks,
Spray some ing like WD 40 FROM A TRIGGER PACK ) all around the carb to engine area.
If it makes a difference then you have an air leak.

Thanks Bert for the suggestion on the air leak.
I started to look at it tonight with intentions to do your spray test, then got the thought that I should just check the fuel pump, since it was one of the few things I haven't checked. With the fuel line off in a can, It seemed to work as it should. I put it back together to start the spray test, but the engine started and ran perfectly; no hesitation in starting and no backfiring. it ran constant and the governor wasn't working back and forth to keep it running. It was smooth at all speeds.
I didn't get to your test, but I'm not very satisfied that it just started working. I don't like unanswered results. So my question to both you and ILLengine or anyone else that might be following this post, is; could just the fuel pump have caused a lot of the backfiring that was previously happening? Could just having the pump run 1/2 cup of fuel into a can, could this have corrected the problem? Do these air operated fuel pumps have a track record of problems? and should I just try changing it out. (I really don't like to just change things out without a reason).
Thanks again sooooo much for your assistance. I feel blessed to have had your help.
I'll put it through a good run tomorrow and see if the trouble is really gone!
Thanks Rex

 

[bertsmobile1]

There is nothing to an impulse fuel pump.
hose from the sump on one side of a diaphram spring on the other and a pair of one way valves.
Problems
1) connected the wrong way round
2) leaky, perished hoses
3) blocked air vent
4) very rare rupured diaphragm

They usually do not give a problem till they don't work.
The pump can move about 10 times the fuel that the engine can consume.

So usually they either work or they don't work

 

[ILENGINE]

Like Bert said, they either work or they don't most of the time. I have seen a few exceptions to the rule though. If the fuel pump wasn't putting out enough fuel it could cause the backfiring because the engine is running lean. Now by allowing the pump to move fuel unrestricted could of cleared when ever was causing the lack of fuel flow. this could be permanent or temporary, Either way if it messes up again just replace the pump.

I have seen the vacuum pump on briggs stop working when the engine would get hot. I have had brand new Kohler fuel pumps not work out of the box, until you actually got fuel into the pump to wet the diaphragms and get it working So there are a few exceptions to what would be normal.

 

[mr.farmall]

There is nothing to an impulse fuel pump.

They usually do not give a problem till they don't work.

Thanks Bert;
Australia is a long way away, but your information is Golden.
Rex

 

[mr.farmall]

Like Bert said, they either work or they don't most of the time. I have seen a few exceptions to the rule though. If the fuel pump wasn't putting out enough fuel it could cause the backfiring because the engine is running lean. Now by allowing the pump to move fuel unrestricted could of cleared when ever was causing the lack of fuel flow. this could be permanent or temporary, Either way if it messes up again just replace the pump.

Thanks so much again, all you have posted must represent lots of experience and knowledge. Thanks for sharing it.
P.S. If I were back east, I would mind spending some of the retired timeto work with you a month or two!! Maybe something would rub off!
Rex

 

[bertsmobile1]

Rarely get a roblem with impulse pumps, however those mechanicals on the CH Kohlers are the bane of my life.
By now I would expect that I would check them first , particularly with the magic over filling oil syndrome but nope, usually the last thing I look at

 

[mr.farmall]

The engine stared and ran well today. I think it's back in service.
I had such a hard time finding the correct wiring schematic for this mower that I ended up metering out all the wiring and making a schematic. I think I'll post it separately for anyone else that might need it.
thanks again everyone.
Rex