40 hp Johnson idle issues

gman01

Recruit
Joined
Nov 26, 2008
Messages
4
I have a 2000 30 HP Johnson jet, which is effectively a 40 HP motor (737cc). My problem is that it idles very rough and seems to smoke more than I would think it should. The idle will shake the motor considerably and will sometimes stall. When I attempt to adjust the low speed needle valve, it does not seem to respond to any changes in the settings, until I turn the needle all the way in. Other wise the motor runs fine, with plenty of compression in both cylinders. the boat sat for aq couple years before I bought it, so I am new to it and am just try to get it running reliably.

Anyone have any suggestions? I have run gas treament for water, drained the bowl and cleaned the low speed jets.
 

HybridMX6

Senior Chief Petty Officer
Joined
Oct 22, 2008
Messages
676
Re: 40 hp Johnson idle issues

How thoroughly did you clean the carbs? There is a good write-up on doing it very thoroughly by tashasdaddy. You will need rebuild kits for each carb, and it is even suggested to use wire or something to fish through the small openings in the carb to get every little thing out and all passages clear.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 40 hp Johnson idle issues

diagrams here, http://shop2.evinrude.com/ext/index.aspx?s1=bf6ad09c53cead335fcfd8a6471c0f7f
you have a high speed and low speed fixed jets, and then you have the low speed air mixture screw. if the fixed jets are not removed and cleaned you will never get it to run correctly. you need kits for each carb, do not mix up parts and make sure the jets get back in the correct places. i have mixed them up before.

carb cleaning http://forums.iboats.com/showthread.php?t=244013

also read this. http://forums.iboats.com/showthread.php?t=158086

also what is your model # there is a 30 hp jet, and a 40 hp jet.
 

gman01

Recruit
Joined
Nov 26, 2008
Messages
4
Re: 40 hp Johnson idle issues

Thanks for your excellent input. Any recommendations on where to purchase the rebuild kits and what brand to use? Oh, and it is a 30 Jet, but when I use the Solec manual I always have to use the 737cc (40hp) directions, as that is what the motor is, to the best of my knowledge (let me know if I am wrong). The model # is J30JRSSB.

Also, this was a tiller controlled motor and I converted it to a remote control. I set the shifter to only shift the jet (F-N-R) but did not connect any linkage to the internal shifting, which I am "assuming" is only for if you have a lower end with prop. I know the tiller shifter switched the internal shifter, but it seemed to only lock the flywheel when not in Neutral for saftey. Is that correct?

Thanks again and have a wonderful Thanksgiving!
 
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