Engine problems on JD 3300(combine), any thoughts?

[Robert_in_NY]

I have been working on the gas motor on the JD 3300 combine for about a week now and it is still acting up. When it is cold it runs fine, but as soon as it starts to heat up it starts sputtering and backfiring. I do not have much experience trouble shooting gas motors and hopefully someone here will have an idea what the problem might be.

Here is a list of things we have done since the problem started (some are not related but while the machine was down we did them anyway). Rebuilt the carb, alternator and water pump. Replaced the fuel pump, blew out the fuel lines, cleaned the sediment bowl and filter and cleaned and checked the air filter and pre-cleaner bowl.

I don't know a lot but I am wondering if it might be a head gasket? I have never had a blown head gasket before to know what to look for. What do you guys think? Thanks

 

[Egon]

Check the choke.

Are there any needle adjustments for fuel flow on the carb?

 

[Farmwithjunk]

I have been working on the gas motor on the JD 3300 combine for about a week now and it is still acting up. When it is cold it runs fine, but as soon as it starts to heat up it starts sputtering and backfiring. I do not have much experience trouble shooting gas motors and hopefully someone here will have an idea what the problem might be.

Here is a list of things we have done since the problem started (some are not related but while the machine was down we did them anyway). Rebuilt the carb, alternator and water pump. Replaced the fuel pump, blew out the fuel lines, cleaned the sediment bowl and filter and cleaned and checked the air filter and pre-cleaner bowl.

I don't know a lot but I am wondering if it might be a head gasket? I have never had a blown head gasket before to know what to look for. What do you guys think? Thanks

Stuck valve(s)? Combines sit for prolonged periods of time. Not good on 'em. A 3300, huh? That's late 60's/very early 70's right? (I had a 4400.)

Blown head gasket will usually be accompanied by steam/smoke out exhaust and/or coolant in oil/oil in coolant.

A 3300 in good condition is a rare bird. There weren't a lot of them sold. Most everyone who wanted "small" bought the 4400. I've seen a few in Southern Indiana around the popcorn farms that are common there.

What engine is that? (I'm thinking a 219 cu in 4 banger? 2510/2520 tractor engine?)

 

[whitetiger]

Points. condenser and cap.

 

[Doc_Bob]

I don't know a lot but I am wondering if it might be a head gasket? I have never had a blown head gasket before to know what to look for. What do you guys think? Thanks

Check the compression.
Bob

 

[Willl]

2 bits it's the ignition coil.

 

[Robert_in_NY]

We swapped the coil yesterday and the machine still acts up. Today we will do the points and condenser (we changed the cap a week ago as it had a mark on it and we weren't sure if it was the problem).

FWJ, I do not know for sure which JD motor it is but the combine is either a 70 or 71 model year. The next time I talk to my JD parts buddy I will ask him as he knows a ton more then I do.

Thanks for everyones thoughts on the issue and I will keep this updated as hopefully I will get this thing going.

 

[Ford960]

Could be the condenser.

Run a compression check on it to rule out a blown gasket if that's your concern. I doubt that's the case however.

Make sure that the point gap is correct too.

What did the spark plugs look like? They're color and condition can tell what's going on in they're respective cylinder. I always keep the plugs in order that they came out. The Chilton manuals sold at auto parts stores for different vehicles have a page of diagnostic photos of spark plugs with various indications of the problems indicated. If you have a plug or two that looks different from the others and you don't have the photos then let me know and I will scan them and send to you.

Does this engine run rough under a load or just sitting?
Try it without the air cleaner while running just sitting. If it starts to run rough move your hand slowly over the carb to restrict some of the airflow. The engine will either run worse, quit, or get better and indicate carburation problems. I think that it may be running rich. Any exhaust smoke? A weak ignition system will just magnify the overfueling.

Also, was there any oil in the distributor cap or on the points? A plugged breather can force oil up the dist shaft and cause the engine to run rough when the oil gets on the points. Most of the time though the engine will just quit. It takes a little while to build up the pressure for this to happen, about the time it gets warmed up.

Anyone can tell you however that diagnosing these kinds of problems from afar is a real shot in the dark. Not that you haven't told us everything that we need to know but hearing, seeing, and feeling the engine running and acting up is the only real way to figure out what the problem could be. To that end you could end up doing much more work to fix the problems based on suggestions and guesswork of us well meaning individuals. When my kids call me with a car problem I always tell them that if they called a Dr with a belly ache that they would be told to come in to be checked out. Mechanical problems are the same.

Good Luck

 

[Robert_in_NY]

Thanks for everyones help. We replaced the condenser and still no change so I decided to retrace my steps and check the tank. Pulled the sediment bowl off and the flow was real slow there so I removed the top from the bottom of the tank and the gas just drained as fast as it could. I screened all the fuel coming out into 5 gallon containers to pull out any junk and then looked at the sediment assembly. It was plugged up pretty good in the valve. Cleaned it all out and found a lot of bee's wings from corn harvest (the guy I bought it from must have forgot to put the gas cap on). Anyway, I put it all back together and ran it and that was the entire problem.

On the bright side, I have a fairly new machine now ;-)

So thanks again guys.

 

[Ford960]

That's great news, I know that you're glad to get it going again.