losing power before traction

[farmallpuller2014]

I pull a super h with a 300 engine and on the dyno it it is pushing out 55 hp.(yes the engine has been redone) but when pulling it will still run out of power before it
will spin a tire.Does anyone have any ideas what could cause this to happen.Could it be a governor issue or what.It doesn't seem to rev. any different under a load.Even
when pulled under weighted it still won't spin a tire.Any help or ideas would be appreciated.

 

[Indiana Ken]

55 HP should spin the tires unless you have a crazy amount of weight on the rear tires. When you measured the 55 HP on the dyno were you allowing the governor to open the throttle or was the throttle opened manually? It sounds like the governor is not opening the throttle plate.

 

[D Slater]

If its really making 55 HP the governor must work some. At what RPM was the 55 HP measured? What size tires?
Cam change? Bigger venturi in carburetor? Running class with RPM limit?

 

[farmallpuller2014]

Thank you for your responses.I had my brother take it and had it dynoed by the president of our pulling club,so I am not sure if they manually open the throttle or what I
will check on that.The tire size is 12x38 and they are not cut.It has a M carb. and yes it has a largest ventura that it can.I am new to this so I am trying to learn.It
has a stock cam.It does have the 3 5/8" fire crater pistons and the head has been ported.I am not real familar with the total function and workings of the governor
especially on the H.How is the best way to tell if the governor is working the way it should.

 

[fastfarmall]

Put on a vacuum gauge, that's one one of the reasons that little plug is in the updraft of the intake can be used for.

 

[DK44H]

I have an H that dynos 60 hp. Uncut 12.4s. Depending on the track it will power out in the 4500lb class long before I break a tire loose even in first gear. It all depends on hitch height, speed, and weight.

 

[Lee460]

I have a few thoughts, take all I say with a grain of salt. If you have 55hp on the dyno you have 55hp on the track. I think the governor is working just fine. It's job is to maintane the rpm until you run out of horses and then it will go down. You have a short stroke motor that has a lot less low end torque than a M,400, or 450. Once you start losing rpm you probably won't be able to recover. Plus, porting the head much gains you rpms but you lose low end torque, which you can't afford to lose anyway. I think you are in to heavy of class for the horses you are producing. Like any tractor, go down in weight til you spin out before you peter out. Now if you think you should have a lot more than 55hp, then you may have a governor problem. But I think 55hp is pretty darn good for just a bore & head work. Just my food for thought. Good luck.

 

[Indiana Ken]

To check the governor you could use a vacuum gauge as fastfarmall posted. In this case you would need to know the vacuum readings from the dyno test. This assumes these readings were taken during testing or you have readings from a similar tractor. Note, as the engine is loaded the vacuum reading will drop.

Another way would be to manually open the throttle plate (without the engine running) and note the position of the outside lever/linkage. Then, with the engine under load observe if the governor opens the throttle plate to the full position. I am not familar with how easy it is to see the carb from the seat of your tractor so this method may not be the safe thing to do. However, it does indicate what the govenor does (should do) during operation.

 

[farmallpuller2014]

Thanks to all I appreciate all input.You all give me alot to think about and try.I am not sure if they did a vacuum test on the dyno,I was not present at the time my brother was,it is both our tractor.I just figured there should be a noticeable RPM change when it is put under a load and I don't hear that,is why I questioned about the governor.The 55 HP. WD45 we pull has no troubles spinning the tires and can notice the pick up RPM's under a load,but it runs only the 28" tires so maybe that is the difference on tires spinning easier.We run the H in 4000,4500,5000,but even in the 4000 it will still die out before it spins out.We get alot of first places with it,but it just concerns me about no noticeable RPM's change.Does anyone have any suggestions on maybe a better tire size.

 

[Indiana Ken]

(quoted from post at 17:06:14 06/23/15) Thanks to all I appreciate all input.You all give me alot to think about and try.I am not sure if they did a vacuum test on the dyno,I was not present at the time my brother was,it is both our tractor.I just figured there should be a noticeable RPM change when it is put under a load and I don't hear that,is why I questioned about the governor.The 55 HP. WD45 we pull has no troubles spinning the tires and can notice the pick up RPM's under a load,but it runs only the 28" tires so maybe that is the difference on tires spinning easier.We run the H in 4000,4500,5000,but even in the 4000 it will still die out before it spins out.We get alot of first places with it,but it just concerns me about no noticeable RPM's change.Does anyone have any suggestions on maybe a better tire size.

The purpose of the governor is to maintain the engine RPM as a load is placed on the engine. The governor does this by opening the throttle plate, once the throttle plate is full open the RPM will begin to drop. For normal governor operation, there should not be a significate increase in engine speed as load is applied, engine speed drops as the load exceeds the engine power output i.e. the throttle plate is full open.

 

[fastfarmall]

I am stumped why it wont spin a wheel, and i dont think it's the Govenor not working but why dont u buy a vacuum gauge and some extra hose, so u can attach it to the light bar or the Christmas tree so u can see what the vacuum is doing next time u pull.

 

[farmallpuller2014]

Thanks for the input.I will try the vacuum guage,what is the normal vacuum range should I be looking for?I will also make sure the throttle plate is opening all the
way.If there is any other suggestions I would appreciate hearing them,always willing to learn more to make my tractor better at pulling.

 

[ss55]

"It has a M carb. and yes it has a largest ventura that it can.I am new to this so I am trying to learn."

Could the large carb and venturi be hurting your low speed torque?

 

[PretendFarmer]

There is such a thing as too much fuel. Have you ever checked out your distributor? I had a similar situation with our C. After lots of checking this, and checking that, I discovered the advance springs were rusted up, and it wasn't getting any advance.
Different tracks and pulling conditions can make one H look like a hero at one pull, and like a wimp at another.
[u:a41a547849]What gear are you using?[/u:a41a547849]

 

[fastfarmall]

Don't get me started making up numbers for vacuum, all i know is when u are on a dead pull you'r gauge show show 0 lbs of Vacuum. Lets say your raking hay you maybe got 7-8 lbs of vacuum, that means it's holding back air and fuel because its a light load. Hope it makes sense.