Stroked JD A

[Anonymous-0]

Trying to get my 1938 a running right. It has a 9 inch stroke and 5 3/4 pistons. It runs good until it gets under a load, and then it wants to fall on its face and die. Tried changing the timing and setting the carb, nothing seems to work, any ideas.

 

[1940barnstormer]

Sounds like a timing issue. If you havent jumped at least one tooth on the cam gear your not even close on the timing.

 

[Anonymous-0]

What is jumping the cam gear goin to change? We have a distributor on it so we should be able to move that enough to change timing right?

 

[Little Big B]

Sounds like your running out of fuel or blowing your spark out.. do you have a fuel pump and or a msd box?

 

[Big Jugs]

Have heard that it could be so much suction in cylinder it doesnt let valves close. I had one like that....had tractor apart for other things and took head to shop just to mag again and check over-guy gave it valve job and may not have put extra washers under springs...assembled same way and had it timed...would do exactly as you said...fall flat under load.

 

[Josh Blackburn]

Call and I'll give you some ideas 9892775366

 

[strokednpoked]

Did you buy the tractor complete, or buy the parts from someone? Did you build it or have it built?

Call the person who built the motor or the parts, they would know more about the details of it.

 

[Ole Johnny]

When the carburetor is wide open (under a load) there is less vaccuum than any other time the engine is running. I dont think that the 'suction' could hurt anything by the valves not sealling with the springs because when the piston starts back up the cylinder they are closed and would be more likely to remain closed with the compression trying to blow them out the top of the head. I also feel that your issue is lack of fuel..... U may have to put larger fuel lines and fuel feed to it. Check yoru filter system and check the screen inside the carburetor for clogging. If you get enough fuel for the air going in it, then it has to run or backfire. If you dont find any restrictions in the lines, try setting the high speed jet open more( half turn or more) to see if you get black smoke and if the smoke goes away under the hard pull,, its starving for gas. If it does its carb time..

 

[Anonymous-0]

What are you running for a carb. and cam? What degree is the cam and your dist. timming set at?

 

[BushogPapa]

Check with Ray, at "Extreme"...he has has good results with what he calls his "Carb-O-Matic" remote Carb adjusting fixture..

Ron..

 

[BushogPapa]

Check with Ray, at "Extreme"...he has has good results with what he calls his "Carb-O-Matic" remote Carb adjusting fixture..
His "B" was probably Larger than your "A"..

Ron..

 

[1940barnstormer]

You cant even start to get enough advanced timing out of your distributor if you havent jumped your gear or done some other timing adjustment. If you have a nine inch stroke and not enough advanced timing it will act as if you have a dirty carb once you get it under a very heavy load.

 

[42 M]

Check the sediment bowl . My A did the same thing when on a plow found the hole letting fuel in from the tank was plugged with a bug. Tractor would run 3/4 throttle but no more.

 

[gtx1967jewison]

So you actually think that if as an example the exhaust valve is sucked open during the INTAKE stroke, this will have no effect?! LOL good luck with that.what good is valve timing & cam design if you free- ride it? Prolly don't need front tires either cuz they'll be off the ground!

 

[Ole Johnny]

I dont follow your reply but if you are saying that the exhaust valve is stuck in the open position when the intake stroke happens then it would also be stuck open as the compression stroke happens and the charge would blow out the exhaust and backfire when the ignition happened on the other cylinder. A stuck valve would be like a badly burned valve and it would be obvious. I feel that the problem with this tractor is LACK OF FUEL. Now the cause is yet unknown but CAN be found if systematiclly approached. Start at the easiest thing to check or alter and work toward the hardest. The person that offered a 'bug in his fuel line' is on the right track i feel.

 

[jd b puller]

I know this is going to come out sounding like an arse, but I'm not sure how anyone could make an intelligent suggestion based on what's been given for info.

Did it used to run good and now has troubles, or is it just now going together?

Compression? Timing? RPM's, What head and what's been done to it? Cam Spec? What carb, and has someone "fixed" it? What fuel?

just changing them to something different doesn't mean you're going in the right direction or chasing the right animal.

On the carb adjuster, i've looked for that video but can't find it of the "carbomatic 9000"

What this is is a remote control load needle adjuster I made for 'on track' tuning. Push button switch mounted to the steering column that activates a small DC motor that turns the load needle on the carb. Watch the pyro and listen/feel the motor while under load.

 

[Anonymous-0]

Hey Ray will you sell my solenoid valve with oil cleaner and some strategically place tubing . For the vacuum leak at full song and a no vacumm leak at idle . Should make the servo just about back the needle all the way out of the carb at full engine song. Air it doesnt always need to go through the carb to get into the cylinders . I cant patent it or nothing harry hyde come up with it in 88 .