Jinma hand throttle.

Catch95 · Feb 14, 2014

Finally raining in Australia in our area after months of drought. Another few weeks and we would've had to sell off our stock. This time last year I nearly lost my bridge in a flood!

Spent today replacing the oil seals in the right steering knuckle on my Jinma 204. Did the left one last year. Lot faster once you've done it once.

Issue now is the hand throttle which I mentioned in a previous post. Got caught in a tree branch and bent hard forward. Now no change to revs when moved forward or back. Can't see a break in the various linkages.

Any thought as to where i should start?

Thanks

Mark

greg_g · Feb 15, 2014

Did the linkage diagram I uploaded last week not help with that question?

//greg//

Catch95 · Feb 16, 2014

Greg,

Thanks - I did use that diagram but while I've worked out the problem, I haven't manage to fix it.

Referring to the diagram of the Engine Control Mechanism II - the problem is Part No. 9 (the sector arm) is rotating freely on the shaft. It should be locked in with a pin - Part 8. I think this has sheared off. I can find the hole on the sector arm, but can't line it up with the hole on the shaft (Part 10). Suspect the remainder of the pin may still be in the shaft.

Is it possible to remove the whole assembly without unbolting the brackets (Part 7). One end of the shaft arrangement is the left arm (Part 17) which is held on the shaft at one end by another pin. The other arm is a solid part of the shaft (Part 10).

Seems that removing the bracket, the bolts for which aren't that accessible, is one way to get it out and remove the remainder of the pin and fit a new one. The other would be to remove the pin on the left arm (Part 17) and slide it out. But that means getting out the pin and then putting in a new one 9 once I'd put the other pin in Part 9..

Any thoughts?

Many thanks

Mark

greg_g · Feb 17, 2014

I've never had cause to remove the linkage, so I can't really answer the question based upon experience. And deciding upon an approach based upon the diagram alone, can't take into consideration work clearances. That said, the diagram suggests you should be able to (a) remove #10 temporarily, so that you could unpin and pull #9 out of the bracket. Once removed, you should be able to find and remove the suspected broken roll pin. Do you have a roll pin tool? Broken roll pins on Chinese tractors are quite common, so a removal/installation tool makes a nice addition to the tool box.

//greg//

Catch95 · Feb 17, 2014

greg_g said:
I've never had cause to remove the linkage, so I can't really answer the question based upon experience. And deciding upon an approach based upon the diagram alone, can't take into consideration work clearances. That said, the diagram suggests you should be able to (a) remove #10 temporarily, so that you could unpin and pull #9 out of the bracket. Once removed, you should be able to find and remove the suspected broken roll pin. Do you have a roll pin tool? Broken roll pins on Chinese tractors are quite common, so a removal/installation tool makes a nice addition to the tool box.

Greg,

The linkage arm #10 is welded on or formed as a part of the longer rod. It is #17 that will have to come off at the other end via removing pin #8 - which I'm not sure if I can do. Hence the question re the bracket.

Thanks for your advice on the roll pin tool though. Seems like the best place to start!

Mark

Catch95 · Mar 2, 2014

An update. I did the repair today. Un bolted the bracket - not easy to access and took the whole rod out. Removed the roll pin holding the arm on the carby side so I could slide off the hand throttle mechanism. Drilled out the the sheared off roll pin and put in a new one. Replaced the roll pin on the other arm and re-assembled. Just need to ensure you have both arms in the right configuration.

Worked perfectly. Put on the fertiliser spreader and the spreader gearbox disintegrated on the first turn...

Mark