90% there, still have a Idle issue.

[obxleadlineman]

I purchased a rebuilt 1988 70hp Johnson recently. So far I have fixed the expected problems. Replaced all the hoses, even all the way to the tank. Eventually the primer needed rebuilding. Had a flooding problem, turned out to be leftover rubber pieces in the needle and seat. Ran great for a few weeks, even got the idle in gear set to 800 rpm. Then idle became a problem again. Turns out the base of the middle carb was warped, sanded all three flat and this fixed the lean condition. In the middle of all that, the stator starts putting out only 150 volts. Purchase a DVA adapter, figure that out, which leaves me where I am today. Oh yeah, also put in new reeds, and sanded the reed boxes nice and flat. Motor runs great, just can"t get the idle in gear down 800 rpm again. I had it right once, so I am really puzzled what I am missing? Any suggestions?

 

[boobie]

Re: 90% there, still have a Idle issue.

Are all the throttle plates closed ? Is the timer base free and returning all the way ??

 

[obxleadlineman]

Re: 90% there, still have a Idle issue.

The butterflies are correct. The timer base is free and lubed up. In the service manual, the method for setting the pick-up timing is Method 2. Remove the throttle cable, make sure the cam is not touching the throttle linkage, and set the throttle to 725 rpm, idling in gear. Then you adjust the cam and roller. I just can"t get it to idle below 1000 rpm without shutting off. Maybe I will borrow another tach, my engine analyzer is only 30 years old. Anybody recommend a inexpensive tach?

 

[Haffiman]

Re: 90% there, still have a Idle issue.

Oh yeah, also put in new reeds, and sanded the reed boxes nice and flat. Motor runs great, just can"t get the idle in gear down 800 rpm again. I had it right once, so I am really puzzled what I am missing? Any suggestions?

This might create a problem at low idle if surface is too 'polished' or the reeds are pressing too hard towards the block. Adjusting reeds and blocks is normally not what I would recommend a DIY.

 

[obxleadlineman]

Re: 90% there, still have a Idle issue.

Well, the reed boxes are flat now. Used a piece of flat wood, 8x10 pane of glass, 320 sandpaper, and water. They were not flat, and you could see daylight around most of them. Installed Cris Carson sport reeds. Just won't idle in gear low enough and long enough without shutting off. The tube that contains the idle circuit feed tube, the one that runs from the bowl to the throat, is cracked the length of the tube in one carburater. That a problem?

 

[fishfeatures]

Re: 90% there, still have a Idle issue.

Well, the reed boxes are flat now. Used a piece of flat wood, 8x10 pane of glass, 320 sandpaper, and water. They were not flat, and you could see daylight around most of them. Installed Cris Carson sport reeds. Just won't idle in gear low enough and long enough without shutting off. The tube that contains the idle circuit feed tube, the one that runs from the bowl to the throat, is cracked the length of the tube in one carburater. That a problem?

I had cracked emulsion tubes inside a carb before (60 hp johnson 1990), had idle issues too with the motor, this stopped when I picked up a cheap carb set off the net.
Cracked tube may be your prob.

 

[boobie]

Re: 90% there, still have a Idle issue.

In answer to your cracked tube, yes it's a problem.

 

[obxleadlineman]

Re: 90% there, still have a Idle issue.

Darn, anyway to seal it, or replace the whole carb? Can't be anything hard like an epoxy, would not be good in engine if it flaked off.

 

[fishfeatures]

Re: 90% there, still have a Idle issue.

have heard that silver soldering the crack can be successful, didn't try it myself but I think a search on here will throw up something on it.

 

[obxleadlineman]

Re: 90% there, still have a Idle issue.

I just bought a single carb on ebay, I will research how to fix the old one also.

 

[fishfeatures]

Re: 90% there, still have a Idle issue.

let us know if it sorts the issue for you, I'd like to think it will. post back ..

 

[obxleadlineman]

Re: 90% there, still have a Idle issue.

Will do, it will be a few days, e-check clearing and shipping. Thanks for the help so far.

 

[obxleadlineman]

Re: 90% there, still have a Idle issue.

YEAH, YEAH, FINALLY, the cracked emulsion tube was definitely really hurting my idle in gear. Got a old carb off ebay, rebuilt it and could tell from the first time I fired it up that it was a better with the new carb. I had a lean condition earlier, and this carb had a very bowed base. Sanded it flat and fixed the air leak. The cracked tube may have come from the distorted base. Mechanic, previous owner, somebody had bowed the base ALOT. Anyway, THANKS FOR THE HELP!!!!!. MY LOCAL MECHANIC DIDN'T NOTICE THIS, OR THINK THIS COULD BE A PROBLEM, THANK YOU FOR THE HELP!!!