Slacking valve

[woodster]

the screw will have to come out through the bottom of the rocker then ...but make sure there are no burrs on the threads where your slotted screw driver goes and you will more than likely have to pull the rocker assembly to do that..if the screw.. screws up and down in the rocker with out the lock nut and doesn't feel loose or hard to turn it is probably OK..but the side to side motion of the rocker is of some concern just check that all the parts are in the proper order and not worn ...all though it would be a rare case the socket in the adjusting screw could be worn or even the top of the push rod but most unlikely but do check ....i still thinking there is something other than that valve causing the problem with rpms in the under the froward gear mode

i am thinking this is not a common problem with the valve train ...this would be a very rare occurrence for this unless some one physically caused this problem with the adjusting screw on that rocker arm but its OK to pursue this if you think its a problem there have been crazy er things happen to small engines but it is usually humans that cause these strange things ..not saying that you did

 

[Ken13559]

Woodster thanks. Noted on the adjusting screw thread. Will look into the thrust washer. Rather odd that rocket arm had that much side to side play.
Crazy isn't my middle name so I'm ok

 

[Ken13559]

I've checked. Washer for #1 rocker arm is in place, however the gap is 0.05mm. Perhaps that's the reason why I can jiggle the rocker arm. I checked #4 rocker arm, unable to fit the 0.05 feeler gauge in between rocker and washer and could not jiggle it.
I've yet to remove the adjusting screw as I plan to make a trip next weekend so don't want to spoil the plan by breaking the engine now.
Will do it another day.

 

[kloudie1]

Sorry, Ken, I have a tractor cross reference for the 3GMF, but not for the 2GM20F.. If ya do a little research based on engine displacement you should be able to find the model tractor that the engine was used in.

 

[kloudie1]

Concerning side clearance of the arm, It looks to be determined by the spacer and circlip AND the position of the rocker arm shaft.. a minor change in the fore/aft position of the shaft will change the arm side clearance. The shaft looks to be retained by a set screw in the top of the aft shaft support.. You could loosen that setscrew and tap the shaft slightly to slide it forward?? From what you are saying about the engine running, I wouldn't mess with it..

 

[Ken13559]

Kloudie, I didn't realise the shaft could be adjusted fore-aft. Thanks for that piece if info. Will check it out after next weekend trip.
I did tried very hard not to mess with the engine but you know sometime its the itch that need to be scratch yet afraid that it may burst the blister

 

[kloudie1]

Ken, I don't think the shaft has a lot of travel (there may be a locating hole for the screw), but it may be able to be moved about half of the "looseness" distance so that both front and back arms have the same clearance.. again, I don't think I'd mess with it.. but I certainly understand the itch ! The only thing that is really critical up there is that all the valves have some clearance when the engine is hot..