Johnson 40 Hp Motor running rough

[said]

It started fine. I started with choke, then I put on Choke off after a minute or so, then I took off just fine. But after couple of minutes it started running rough and lost power. I was lucky to get back to the ramp.
I just cleaned the gas tank and refilled with fresh mix. The tank is very clean, no rust.
Any suggestion would be great.
Thanks

 

[DJ]

Re: Johnson 40 Hp Motor running rough

More info, please.

Year.

Model.

 

[said]

Re: Johnson 40 Hp Motor running rough

I am sorry it took me this long to answer.
On the motor cover it says: Johnson 40 Electric Starter Super Sea-Horse and on the lower unit it says Superquiet.
I found the serial number: 2012083. The model number is covered under the motor so I couldn't get to it. And I don't know the year.
Is there a way to find out just from the serial number?

 

[Monte1961]

Re: Johnson 40 Hp Motor running rough

check compression, Spark and timing. You can also try to fog carbs when it acts up to see if that helps. Post back results and welcome to iboats.!

 

[said]

Re: Johnson 40 Hp Motor running rough

Monte1961. I am not much of wrench guy but I will try to get this. Is there some good paper or link that might help?

 

[said]

Re: Johnson 40 Hp Motor running rough

Can anyone tell me what type of crbs is this one? Thanks.

 

[lindy46]

Re: Johnson 40 Hp Motor running rough

That is a carb with a hot water choke - from an early 1960's 40hp. I think that was only used a couple years - they changed it I believe in '63.

 

[said]

Re: Johnson 40 Hp Motor running rough

I got couple of Johnson/Evinrude Outboard maintenance book and they refer to carbs as type I or II or III.
Do you know which type it is?

 

[Monte1961]

Re: Johnson 40 Hp Motor running rough

Year make and model would sure help us to help you. If you could or have that info, We could tell you more! Post back

 

[said]

Re: Johnson 40 Hp Motor running rough

All I have is:
Johnson 40 Super Sea-Horse - Serial# 2012083

 

[lindy46]

Re: Johnson 40 Hp Motor running rough

You need the model number - but if the carb pictured is the one on the motor, it is most likely a 1961 or 1962.

 

[said]

Re: Johnson 40 Hp Motor running rough

Yes the carb is on the motor. Thanks. But my question still remain. Which type is it I,II, or III?
I think I found out why I was not getting full power while I thought it was running rough.
While putting back toghether the shift cable because it likes to slip from the screws in the shift master box, I noticed the throttle cable cannot go further than half of the travel. Its travels ends at the middle. I had that cable replaced by a shop last year but didn't have a chance to take it out in the water afterwards. I think my throttle cable needs some adjustement.
Is there a good walk through that might help a challenged mind?
Sorry the model number is right under the cover and cannot get to it.

 

[lindy46]

Re: Johnson 40 Hp Motor running rough

Yes the carb is on the motor. Thanks. But my question still remain. Which type is it I,II, or III?
I think I found out why I was not getting full power while I thought it was running rough.
While putting back toghether the shift cable because it likes to slip from the screws in the shift master box, I noticed the throttle cable cannot go further than half of the travel. Its travels ends at the middle. I had that cable replaced by a shop last year but didn't have a chance to take it out in the water afterwards. I think my throttle cable needs some adjustement.
Is there a good walk through that might help a challenged mind?
Sorry the model number is right under the cover and cannot get to it.

Not sure what you mean by Type I II or III. That motor would have a Model C carb with a hot water choke. Did they replace the throttle cable with a new one? Restricted travel usually means someone has cut off the inner cable, making it too short. Also, there is a thumbscrew adjustment on the motor end - try adjusting that so that the cable pulls the lever to the wide open throttle position.

 

[clw426]

Re: Johnson 40 Hp Motor running rough

If the motor is in neutral, the throttle will not move all the way. This is to keep from over revving the motor.

 

[said]

Re: Johnson 40 Hp Motor running rough

Yes I had the throttle cable replaced with a new one.
I will try your advice and clw426's.
Thanks.