massey 65 backfires / low performance

jpryorx2 · Apr 9, 2015

hey guys i have a 1964 massey 65 that is running like crap. i bought it last year after it had been sitting for 10 years changed all the fluids and rebuilt the carb and did a tune up right away. fired it up and within a few minutes it was pouring oil out the bellhousing turned out to be a bar rear main seal so i replaced the clutch and all the seals on the trans side also. right now it will fire right up and idle fine for about 5 mins then it starts backfiring out the exhaust. it doesn't seem to be random almost like it's every time a certain cylinder fires.after it's fully warmed up it stops backfiring but seems to be lacking power i've been running in low 2nd any higher gear and it wants to stall out. it had new rings before it was parked for the 10 years. i was thinking somthing going on in the head but just did a dry compression test and had 100-110 on all cylinders. i had replaced the plugs last weekend and ran it about an hour but noticed today that 3 of the plugs have soot or carbon on them and the forth still looks like brand new. i double checked and all cylinders do have spark. does anyone have any ideas?

jtwat · Apr 9, 2015

Sounds like a valve sticking open when the engine is cold. Have you done a compression test with engine cold?
The one clean plug indicates that cylinder is not producing power.

jpryorx2 · Apr 9, 2015

yes the compression test was cold it hadn't been started in a week.

Tony in Mass. · Apr 9, 2015

When you say 'after 5 minutes' that reminds me of a dying coil or condenser. A skip after a few minutes can sound like a cracked dist cap when it starts to warm up- could still be a valve thing, but far easier to get to an electrical thing if you are lucky enough for a quick fix. Good luck.

jpryorx2 · Apr 9, 2015

sorry didn't mention that i have tried 2 other coils and it still does the same thing. after at full temp which show (about 150 on my gauge) it will stop backfiring. at that point i can use it but in my opinion it is highly lacking power.i can never use high range and in order to climb any inclines i need to use low 1st and turn off the mutipower alot of the time or else the rpms will drop and it will stall if i don't press the clutch. i was happy that compression was good but now it's driving me crazy trying to figure out why 1 plug looks like new. the intake valve on that cylinder being stuck closed would make sence. but would i still have 110psi in that cylinder since the air couldn't get in? is it worth putting some marvel mystery oil in the oil and gas and running it this weekend? it's first job of the season is digging up a bunch of saplings which i can do at idle but plan to be plowing and discing my food plots within the next couple weeks. also not sure if it a symptom or not but this thing drinks gas like crazy. 5 gallons last me about 2 hours of use when running about 1000-1200 rpm.

2tractors · Apr 10, 2015

Sounds like plug wires crossed or timing or even wrong direction.

Tony in Mass. · Apr 10, 2015

Yeah... he's burning gas faster than you and me can drink Carling Black Labels huh 2?
These are kinda big gas engines, so not so efficient. A gallon and a half an hour doing some serious work, but over 2 is too much, wouldn't you say 2?
Like 2, I wonder if your distributor shaft works loose, or hopefully nothing worse, but maybe your timing is drifting.
I don't do the light/marks thing- we-need 2 people, even if one is a kid- we always just pull the throttle wide open, find a steady roar, then find the place where it will tear wide open...AND sit at a slow idle. Usually just a few degrees of twist. THEN torque the dist shaft tight. I'm still betting on a cracked cap, but loose wires would be a free fix huh???? We'll hope for that.
BTW, I wouldn't fret over one 'clean' plug, it's the oily ones that bear bad news.

Our Farmer · Apr 10, 2015

Sounds to me ignition related. Your compression is good for a tractor that's been sitting that long, will probably come up with use. You can pull the valve cover and turn the motor by hand to see of the valves are opening or not. If the valve was stuck that hard, you'd probably see a bent pushrod. If she's been setting that long, could be a dead mouse or crap in the intake runner for that cylinder. Could also be a massive vacuum leak in that cylinder, like a leaking intake gasket.

But my bet would be ignition related.. If the spark doesn't advance with rpm, you'll drink fuel. Get yourself a timing light and see that the timing is set, and advances properly. Point gap is .022, initial timing is 6 deg btdc, advance at 2000 rpm should be 26 deg btdc. If the light shows timing wandering all over the place, check your dist drive gear and shaft bushings.

I assume you've installed new points, condenser and wires?

jpryorx2 · Apr 10, 2015

the tractor is at my hunting property but i plan to be there tomorrow. i picked up a new set of copper core wires and a new timing light and will also double check the point gap. it seems to me that the clean plug would mean that cylinder isn't getting any gas.

jpryorx2 · Apr 13, 2015

ok so i got to work on it last weekend and reset the point gap and regapped the plugs. i noticed that i had put carbon core wires on it so i picked up a set of copper core. then i found my problem aparently i've been running it for a year with the fireing order wrong. it was firing 1-4-3-2 and my book shows it should have been 1-3-4-2. after putting the new wires on right and readjusting the timing other then a little stumble every now and then shes running better then ever before

massey 65 backfires / low performance

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