YM1700 - Runs Wide open - fuel injector/governor issue?

rockrr · Jul 4, 2017

Hi folks - new to the forum - great information throughout! I have a question, I am needing some help with - I have a YM1700 -2cyl that when I start it, it will only with run at full throttle. The throttle control has no effect and will only shut off if I cut the fuel. I thought maybe I had a stuck injector rack, so I removed the fuel injector pump and cleaned and inspected everything on it - all seems to be working smooth and pumping fuel. Does this sound like I have a governor issue - maybe something with the fly weights stuck or broke? Any good way to test the injector pump, as they are $$$ to buy a new one just to rule it out?

Thanks!

thepumpguysc · Jul 5, 2017

Its possible the gov is screwed up BUT they usually go the other way.. NO START.. I've never seen one break a spring or flyweight & go wide open..
If you want, I can check the pump & injectors for ya.. before buying new.. might save you SEVERAL HUNDRED $..
If you want to pull the pump again... OR.. if you can reach the engine control rack w/o pulling the pump..
MAKE SURE the ENGINE rack is moving back & forth..

winston1 · Jul 5, 2017

Thinking thepumpguysc is talking about pulling the plate shown right above the pump and make sure the rack can be moved back and forth. FUEL_SYSTEM: Yanmar Tractor Parts

rockrr · Jul 5, 2017

Thanks - yes I did remove the inspection plate and the rack looks to move freely when engaging the throttle control lever. Do you feel this points to a bad injector pump? I have taken the pump completely out and cleaned it the best it can be, but same issue on re-install. I know that if I slightly loosen the two ports on the pump that the fuel lines connect to, that the fuel will just pour out of them - which I believe should be the case looking at the design of these pumps. With the fuel lines off, upon starting they do "spit" fuel out, but I have also noticed sometimes I may only see fuel out of one port. the racing of the engine to max rpms is what is throwing me off here - I have to suspect that I have a bad pump as governor issues always seem to point to other problems seen and not a tractor that runs full rpm. Let me know if I should be looking at anything else. I found one site that sells a new pump for 350 dollars - sure would like to find another cheaper option.

Thanks!

winston1 · Jul 5, 2017

Did you run it with the plate off watching the rack movement? By the way, welcome to the forum. :welcome: What part of Texas are you located?

rockrr · Jul 5, 2017

Thanks - I did run it for a bit with the plate off but the governor seems to pull on it pretty hard.

Winston1 - I am close to Royse City - so west of you a bit.

Thanks!

thepumpguysc · Jul 5, 2017

I can look at it for ya.. all it will cost you is shipping back & forth, unless it needs something that I dont have.. which is RARE..
Send the injectors too..is it BLACK/WHITE smoking when running>> just send me a msg. for shipping address.

rockrr · Jul 5, 2017

thepumpguysc - thanks -- I'll send you a msg for address. When it runs it is dumping black smoke.

rockrr · Jul 5, 2017

So was getting ready to pull the pump and I ran another test. With the engine off, the injector rack moves freely back and forth with the throttle control arm. When I start the tractor the rack does not move at all and again the engine races (thought the thing was going to blow up before the fuel cutoff happened). This leads me to believe that I must have a governor issue??? Thoughts?

Thanks!

normde2001 · Jul 5, 2017

rockrr said:
Thanks - I did run it for a bit with the plate off but the governor seems to pull on it pretty hard.

Winston1 - I am close to Royse City - so west of you a bit.

Thanks!

I don't know what that means, but did you watch the rack movement? Does it move end to end with the throttle movement. If the governor is interfering, you have a governor/linkage problem, not a pump problem. Hands-on troubleshooting required.

thepumpguysc · Jul 5, 2017

Might as well get the fuel system checked out aslong as its free.. I don't offer it ALL the time..
Seeing you've already messed w/ the pump.. you might be fighting multiple problems..
I can straighten the fuel system out, but once it checks out.. you STILL might have a linkage/ governor issue..
BUT ATLEAST we'll know what it AINT.. lol
OR you can spend 300. for a pump & 300. for injectors & poke & hope..?? lol
Smart money says, I'll be seeing a package..lol TPG

rockrr · Jul 5, 2017

thepumpguysc - yes sir you know you will be seeing a package. Need to rule out stuff the smart way. Now my Ford 9n Steering broke (steering gear sheered off)- always something fun around here. Guess thats what I get for using old equipment - but hey somebody has to use it! lol

winston1 · Jul 6, 2017

I am understanding the rack moves freely. Sure points toward governor problems. Seems the governor is holding the rack in high speed position. Can you confirm that?

rockrr · Jul 6, 2017

winston1 said:
I am understanding the rack moves freely. Sure points toward governor problems. Seems the governor is holding the rack in high speed position. Can you confirm that?

Yes sir - the rack moves free when the tractor is off. When I start the tractor it stays wide open.

winston1 · Jul 6, 2017

If you push on the rack while running I assume you have considerable resistance. Unable to move it in order to slow speed? If so, seems to me it has to be governor problems.

rockrr · Jul 6, 2017

Correct, I can't move the rack while it's running. Maybe I should unhook the linkage to the rack and start it and see if I can manually slow it.

normde2001 · Jul 6, 2017

Do you have a foot throttle, and is it by chance stuck down, broken spring, bind, etc? My YM 2000B would not shut off by hand throttle at one time, caused by weak foot throttle spring not fully restoring foot throttle.

careyo63 · Jul 6, 2017

I agree it cold be the throttle linkage. I believe at #22 on Hoyes Dia. will be a easy way to remove and check
it. That may rule out the pump if everything is working correctly moving it by hand.

rockrr · Jul 6, 2017

normde2001 said:
Do you have a foot throttle, and is it by chance stuck down, broken spring, bind, etc? My YM 2000B would not shut off by hand throttle at one time, caused by weak foot throttle spring not fully restoring foot throttle.

Good point - but in this case the foot throttle seems to be working fine. I am going to disconnect the linkage to the rack and try a quick test. be back in a few with the results...