John from Illinois - Johnson 140 4 stroke valve adjustment

[aero320]

I ordered the shop manual and two special tools to adjust the valves on my new Johnson 140 4 stroke. It went very well. All valves gaps were within the specification of .009 - .011" except on which was just shy of .012". The disk was "253" so it will probably take a "257" to bring the gap to .010". My question is, would you make this correction of leave it alone.<br /><br />Thanks for your help.<br /><br />Incidentally, I was very impressed with the attention to detail found on the engine. It reminded me of a Japanese automobile engine!

 

[jegervais]

Re: John from Illinois - Johnson 140 4 stroke valve adjustment

I've got shim charts for this engine and based on what you're telling me, the shim chart says to replace with a 258.<br /><br />Make sure when you install/reinstall shims that the identification number is against the bucket, not against the cam lobe (it will wear off).<br /><br />I guess I would go ahead and change it. How do you like those tools?<br /><br />John

 

[jim dozier]

Re: John from Illinois - Johnson 140 4 stroke valve adjustment

aero It is (basically) a Japanese auto engine, Suzuki has been making cars for some time now, and 4-stroke grand prix motorcylces for even longer. Current champion on the big bike circuit I believe.

 

[aero320]

Re: John from Illinois - Johnson 140 4 stroke valve adjustment

John, I believe the only special tool you have to have is the little wedge tool. The cam will actually depress the tappet enough to insert the tool. I suppose the other tool would be required if the puck had been removed and the wedge tool slipped.<br /><br />John, the markings on the pucks are actually mm x 10, i.e. 250 = 25.4 mm. Each incremental number in the puck labeling represents .01 mm which is equivalent to .00039". I should have taken each puck out and recorded its size. Might have been possible to move them around and get everything in specification. Should I attempt to hit the middle of the range, i.e. .010"?

 

[jegervais]

Re: John from Illinois - Johnson 140 4 stroke valve adjustment

You are correct about the cam lobes moving the bucket far enough, but I do feel the plier tool depresses the bucket further. Also regarding the wedge slipping out, it can and I've had it happen to me a couple of times - I was glad I had both.<br /><br />Ideally, shoot for the middle when you're replacing a shim, but as long as you're in the range, it's good - no need to get overly persnickety about these things, that's why there's a range in the dimension.<br /><br />-John