Got the $150 Taishan 25 running but one more problem

[78sharpshooter]

The lift pump was frozen so I pulled it apart, cleaned it up and it seemed to be fine. Put it back on and then primed it with the plunger and it pushed fuel out the screw at the top of the pump. Cranked it over to purge the lines and fuel was coming out so I tightened the lines and it fired up and ran for 5 seconds on one cylinder then the other started to fire and the rpms started going too high despite moving the throttle to the lowest position and I had to use the decompression lever to kill the motor. Do you think the governor is sticking?

 

[Bob Rooks]

Sounds like the rack is stuck. There is no direct mechanical connection between the throttle and the governor rack. Check the oil level in the pump/governor assembly. If there isn't a dipstick there should be a 6mm tattletale bolt about one third the way up the side of the pump housing. And there may or may not be a 6 mm drain bolt on the bottom of the governor housing - if not you have to syringe it out.
There should be a removable inspection plate on the side of the pump that will reveal the sliding rack.

 

[RonMar]

Or the flyweights(ballbearings) are all gummed up inside their housing. As Bob, mentioned, there is no direct connection between throttle and IP rack. Think of it more like a speed/RPM selector. The governor spring tries to hold the rack at full RPM, the governor flyweights which increase in applied force with RPM, counters this spring force. The throttle lever pulls on the governor spring, increasing or decreasing pressure and the engine finds the RPM where the governor balances this spring force. IF the flyweights are gummed up, they cannot apply the counter force and RPM increases(runaway)...

 

[78sharpshooter]

Or the flyweights(ballbearings) are all gummed up inside their housing. As Bob, mentioned, there is no direct connection between throttle and IP rack. Think of it more like a speed/RPM selector. The governor spring tries to hold the rack at full RPM, the governor flyweights which increase in applied force with RPM, counters this spring force. The throttle lever pulls on the governor spring, increasing or decreasing pressure and the engine finds the RPM where the governor balances this spring force. IF the flyweights are gummed up, they cannot apply the counter force and RPM increases(runaway)...

There is a small black plastic dipstick. When I initially checked it the oil level was below the stick so I drained it an put in 20W non detergent oil. After it ran the first time, I drained some oil and added a bit of the marvel mystery oil thinking it might loosen things up. Can I pull the 2 nuts circled in blue and not have anything fly apart? Or is it safer to take off the cover with the 3 screws? Is the rack what adjusts the volume injected per stroke?

 

[Bob Rooks]

There is a small black plastic dipstick. When I initially checked it the oil level was below the stick so I drained it an put in 20W non detergent oil. After it ran the first time, I drained some oil and added a bit of the marvel mystery oil thinking it might loosen things up. Can I pull the 2 nuts circled in blue and not have anything fly apart? Or is it safer to take off the cover with the 3 screws? Is the rack what adjusts the volume injected per stroke?

Put the MMO back on the shelf. Use the same oil in the pump/governor assembly that you use in the engine. Please reread my previous post about the cover plate and disregard the two circled nuts. I suggest you do some research on diesel engine governors and fuel injection pumps to learn about barrel and plunger assemblies, scrolls and helixes, and why there are no seals in these pumps.

View attachment Fuel IP cutaway.bmp

 

[78sharpshooter]

Put the MMO back on the shelf. Use the same oil in the pump/governor assembly that you use in the engine. Please reread my previous post about the cover plate and disregard the two circled nuts. I suggest you do some research on diesel engine governors and fuel injection pumps to learn about barrel and plunger assemblies, scrolls and helixes, and why there are no seals in these pumps.

View attachment 517784

Got it. Did my homework today and read up on the pump, went out and pulled the cover and the rack was not moving at all when changing the throttle position. Gently pried to slide it and then pulled the back cover on the pump to expose the end of the rack shaft and pushed it back. It took a decent amount of force to move it. Applied oil between each manual movement of the rack and after about 100 times it seems to free up pretty well. Put the back cover on and the throttle position now changes the rack position. Thanks Bob for pointing me in the right direction.

 

[78sharpshooter]

started it up and it ran amazingly well. throttled up well and at minimum throttle position it idled smoothly around 315 rpm. Next up is cleaning out the hydraulics

 

[Bob Rooks]

started it up and it ran amazingly well. throttled up well and at minimum throttle position it idled smoothly around 315 rpm. Next up is cleaning out the hydraulics

Good news. Glad you got it.