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

[rockrr]

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]

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]

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]

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]

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]

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]

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]

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

 

[rockrr]

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]

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.