push rod problem?
 

I have a Saito 72 that I bought used (this might be my biggest problem). The engine has given me quite a challenge to get running properly. the previous owner I feel knew nothing about 4 stroke engines or engines in general and both the low speed and high speed needles were way out of adjustment. I finally got the engine running what I thought was good only to have it quit running all together after 5 or 6 good flights. I took the rocker covers off and I noticed one of the pushrods was no longer "seated" into the bottom indent of the adjustment screw. Is this something that happens from time to time or does this mean I have another problem, possibly a bent pushrod? I don't believe it would be terribly hard to replace a pushrod , they just drop in after removing the rocker arm, am I correct here?

RE: push rod problem?
 

sounds like the guy adjusted the valves with out knowing how... pull out the the push rod adjuster and nut, you can then slip out the push rod, take a look and see if it's bent or mushroomed, also look at the recess on the adjuster for any dents ding's... if you find damage I'd also pull the cam cover and check the lob's. chances are the part's are fine, put it back together(check push rod orientation), set the valves correctly... you should be good to go.


John

RE: push rod problem?
 

Roll the pushrod on a very flat surface to check about it being bent.

If you determine that the valve was probably not much out of adjustment, The problem was that your valve stuck open enough for the pushrod to fall out of it's socket?

Enjoy,

Jim

RE: push rod problem?
 

Just saw this, sorry.

All notes above are good, but I wouldn't pull the cam box off. I'll add only that there is a top and bottom to the push rods on Saito mid block engines. Installed backwards will cause valve train problems.

The upper end has a taper before the half ball, the lower end of the rod has the ball at full diameter. See picture. The upper end is on the right.

Bill.

RE: push rod problem?
 

Over reving can pop the pushrods too, usually from running to small of a prop.