'71 Johnson 50hp running wide open

[PrplGld]

model # is 50ESL71S<br /><br />I rebuilt both carbs and the fuel pump, put everything back together. I put in new fuel lines. It idled roughly on the muffs. I put it in the water and went through the adjustment process which I found here on this forum.<br /><br />The adjustments went fine. Except that even after the engine was warmed I needed to briefly use the choke to get it started and whenever I used the choke the engine would respond by running wide open. Nothing would lower the RPMs except killing the motor. It would start at idle immediately afterwards.<br /><br />I finally got the engine idling nicely then let it rest. I returned to the motor an hour later and it ran wide open regardless of throttle and/or choke settings. Killing and restarting was useless because it still would run wide open.<br /><br />I was tempted to put it in gear to see what would happen but my health insurance isn't very good.<br /><br />Why would it idle fine then later run wide open? After reading quite a few posts the only thing I can guess is there's a problem with the float.<br /><br />I ordered a Seloc manual after this problem (yeah, I know, I know). According to the manual, the only thing I did wrong during the rebuild is failing to replace the low-speed needle valve bearing (the old one didn't come out so I didn't know what the new one was or where it went).<br /><br />Also, there are two nipples on the bottom front of the crankcase. I connected the lower diameter nipple to the same size nipple found on the bottom of the air silencer. The large size nipple was connected to the fuel pump which I vaguely recall was the original setup (this little detail doesn't seemed to be covered by the manual). When the engine was running wide open there seemed to be fuel droplets occasionally coming through the bottom hole in the air silencer cover (the rubber plugs were not present when I obtained the motor). Do these fuel line connections sound correct?

 

[OBJ]

Re: '71 Johnson 50hp running wide open

Well let's talk about the carb rebuilds a little LSU.....did you install new kits? Did you soak the carbs and follow up with air? Float setting correct....with the carb body inverted, the float should be level with the float bowl gasket surface. The needle vlv bearing can be removed by taking a piece of wire and bending a small hook on the end. Shove the hook down into the needle vlv hole and snag the old bearing and pull it out.<br /><br />Did you check the throttle plates closed when at idle and they aren't hanging up? If you did a sync and link, they should be OK....but check them to be sure. Also check the choke plate isn't hanging up either. Make sure the little return spring is good that the solenoid plunger isn't hanging up....this would cause a high idle. The choke plunger can get dirty and not work real well in the hole....so take a good look at this.<br /><br />The connections you mentioned sound right.

 

[PrplGld]

Re: '71 Johnson 50hp running wide open

Originally posted by OBJ:<br /> Well let's talk about the carb rebuilds a little LSU.....

I used new kits. I put the new floats in without any adjustments. The motor was idling perfectly for several minutes after the last adjustment, which is why I was so puzzled about it later running wide open.<br /><br />I sprayed the metal carb parts with carb cleaner and blew them out with compressed air. I did not soak them overnight. I suppose I'll order new kits and start over. Should these metal parts be submersed in a solvent overnight?<br /><br />The chokes were closing completely. I closely observed the electric and manual choke and they both were operating properly.<br /><br />The only metal discs I removed and replaced were the ones covering the openings at the needle valves. I suppose they should all be replaced on my next try.<br /><br />Apparently the fuel pump rebuild was successful, as the motor was getting plenty of fuel.<br /><br />Choke plunger? I don't have the manual while I type this reply and I don't recall this part. Is this the needle which is raised and lowered by the float?

 

[OBJ]

Re: '71 Johnson 50hp running wide open

I was refering to the choke solenoid plunger...that metal round cylinder that fits into the solenoid and is connected to the carb choke plate lingage with a wire spring. It can hang up and not come back out of the solenoid keeping the choke closed. It's seldom you have to remove the choke plate or throttle plates to rebuild the carb. Make sure the choke plate isn't hanging up.

 

[PrplGld]

Re: '71 Johnson 50hp running wide open

Originally posted by OBJ:<br /> I was refering to the choke solenoid plunger...

Oh, ok. It was working fine.<br />Thanks for the help. I'll post back here in a few days when I get everything done.