Ford 9N problem child

[Anonymous-0]

Have a 9 which I use to brush hog my 20 acres on my 6 year old tree farm. Got the tractor 6 yrs ago. Only used in the middle of summer and then at the end again to mow between trees. Anyway it will only hog for an hour now before it blogs down. It barely makes it back to the barn and thats without mowing. Used to do about 10 hours before w/o a problem, then gradually it got worse over the last two years. All four plugs seem to have oil residue on them after said time. Not certain about the oil but thats what I think it is. I did a compression test and came up with 90 dry, all 4 the same. I'm not much of a mechanic so I never did a wet test. Originally thought that since they were the same that was good, but what does the 90 reading tell me? Also my tractor will get a vapor lock if I stall it after its heated up. Won't start again until its cooled down. Don't know if its related or not but giving some background to you. So my question is what is my next step? Take it to someone who knows what they are doing right? Hah hah! Anyway any help or suggestions will be greatly appreciated.

 

[Bob]

Your coil, condensor, or ignition switch is bad, or you have a fuel flow problem.

You compression is just fine for a working tractor with some hours on it, and an engine doesn't typically "b(l)og down" after an hour or so, and then run good after cooling because of compression issues.

 

[Anonymous-0]

Actually to clear things up a bit, it won't run good again until I change the plugs. When I mentioned the vapor lock issue, I was referring to when it used to run great for 8-10 hours. Thanks, sorry about the b(l)og!

 

[souNdguy]

Will it restart with full power if you change out the pkugs and get back to work in a short period of time?

What oil and plugs are you using?

al437 or champion h12 are hotter plugs and may help with fouling if you are using something like a champion h10.. or al 216.. etc.

In fact.. If I had a fouling issue.. I'd ditch the ch plugs and only use AL.

90 psi is good. If your fouling is a big issue.. get anti foul adapters .. it takes some comp ratio away.. but you are doing fine at 90 dry..

Soundguy

 

[BillM (OH)]

Compression at 90 dry is OK. 1 hour run time followed by no start until long cool down is usually the coil - next time it happens, check spark when hot and see what you get. And, as SouNder sez - use Autolite 437's for plugs.