Rebuilt HP Johnson carbs and idling fast

[JamesCoste]

I am pretty sure where I might have messed up.<br /><br />1. Dealing with the low-speed needle valve, I remember fully tighening the needle valve all the way down. <br /><br />Should it be backed off and, if so, how much?<br />The same on both carbs?<br /><br />2 1/2 turns counterclockwise......... ?<br /><br />2. The throttle and choke linkages. When I rehooked them up, there is an adjustment screw on both carbs. I have adjusted them and it does make a difference as far as the RPM's that the engine idles, but It doesn't seem to be quite right.<br /><br />It is running smoothly and when I put it in gear, it just does't do it as smootlhy as I would like.<br /><br />I appreciate any advice anyone can provide.

 

[JamesCoste]

Re: Rebuilt HP Johnson carbs and idling fast

^

 

[Xcusme]

Re: Rebuilt HP Johnson carbs and idling fast

James, <br />Post your model and year....it really helps us to know what motor you have!

 

[JamesCoste]

Re: Rebuilt HP Johnson carbs and idling fast

Oops, you're right!<br /><br />1983 Johnson 50 HP, Model # J50BELCTA, Serial # J5810665<br /><br />History: sat up for 4 years (probably was "winterized" by boat dealer before boat sat up without running). <br /><br />Runs fine one day, runs (almost like on one cylinder) the next. Decided to rebuild carbs. Now idles fast. Have not taken it back out to lake for trial run because of fast idle. Just running on "ears" for now while cranking up. Runs fine and doesn't cut off, but it is idling faster than it should. I don't have a way of testing exact RPMs. Using Clymer's manual.

 

[JamesCoste]

Re: Rebuilt HP Johnson carbs and idling fast

It's times like these that I wish my Clymer's manual was specific for my 1983 Johnson.<br /><br />I've been reading my manual and it get's confusing going from a 1977 - 1986 50 HP to the V4's and V6's etc.<br /><br />Some say to turn the screw for the valve back 1 1/2 turn, some 2 1/2, while my apparent model doesn't say anything.<br /><br />I should have counted the number of times that it takes to fully tighten it (clockwise) and then wrote that down before removing it. <br /><br />(also bumping up ... I need some sort of advice before attempting to fix this in the a.m.)

 

[The Marine Doctor]

Re: Rebuilt HP Johnson carbs and idling fast

Erm....are you sure you have adjustable jets?<br /><br />Try just seating those screws. I am pretty sure there are fixed jets in behind them.<br /><br />That is if its an 1983.<br /><br />TMD

 

[JamesCoste]

Re: Rebuilt HP Johnson carbs and idling fast

Marine Doctor,<br />You are exactly right, I am not sure if they are adjustable jets, but was just doing some reading and guessing. The Clymers manual did not say to turn them back for my year (1983) motor, but some specific other years did say to do so. I've heard that the Clymer's manuals are sometimes wrong (from this forum) and was guessing.<br /><br />I think that my problem lies with the choke and throttle linkage where they attach to the to carbs. I'll play with the adjustments there after reading more in my manual.<br /><br />I'm going to do some reading on getting the idling to a correct speed.

 

[OBJ]

Re: Rebuilt HP Johnson carbs and idling fast

James.....your carbs do have fixed jets. The Clymers manuals are OK for some things but for the best info, get an OEM manual for your engine. They are still available and will guide you step by step through the sync and link process. May save a lot of "playing around".

 

[Boatman]

Re: Rebuilt HP Johnson carbs and idling fast

Another thing to check is that both carbs are opening and shutting fully. IN TIME.<br /><br />Remove the air box and make sure both rear butterflys ar completly closed (look into the carb throats) They should be identical. There are linkage screws on the side of the carbs for adjustments. If you have one carb open a bit further than the other. It will idle fast.<br /><br />The roller on the linkage at an idle should be free and NOT touching the cam.<br /><br />Boat

 

[JamesCoste]

Re: Rebuilt HP Johnson carbs and idling fast

I'm glad that I don't have to fool with the jets since they are fixed.<br /><br />I did some good reading on the link and sync section in the Clymers and it should help me some.<br /><br />I do believe (hope) that my biggest problem is as boatman mentioned "If you have one carb open a bit further than the other. It will idle fast." As I adjusted the linkage screws yesterday, it was making a big difference in the idle speed. If I adjusted them wrong, the idle would be way to high. Also, if I adjusted them wrong "the other way", it would be too slow. I'm going to adjust them today some more. If it starts running at about where it was before the rebuild, I'll venture (with trolling motor and cell-phone) to the local river and run upriver for a test.<br /><br />I do want to get another manual. I spent $37 on the Clymers from the boat parts shop here in Tallahassee so I want to make sure I get the right one this time. I'll have to do some research to make sure I'm getting the right one.<br /><br />Time to "tune"...