'74 Johnson 50 wont idle in water?

M

melvino

Cadet
Joined
Sep 25, 2009
Messages
12
I have a newly tuned up 1974 Johnson 50hp that has had the carbs done, new power pack, new coils and new control cables. It idles great when I have muffs on it in the driveway and all is good. I put it in the water and it will not idle without giving it gas and when I try and put it in gear it just quits (because I can't have it in high idle except in neutral). Why would it idle fine with muffs on it, but not when it was in water? I am perplexed. Any advice would be greatly appreciated!

Thanks,
A new boater
:D
 
M

mikesea

Lieutenant Commander
Joined
Oct 1, 2006
Messages
1,830
Re: '74 Johnson 50 wont idle in water?

the backpressure will take power out,you need to kick the idle up a bit,should have a large slotted screw try a turn or 2
 
M

melvino

Cadet
Joined
Sep 25, 2009
Messages
12
Re: '74 Johnson 50 wont idle in water?

Thanks Mikesea! I see where there is the idle adjustment, but I had a mechanic tell me to adjust the throttle cable, is this not right?
 
M

moonfish

Petty Officer 2nd Class
Joined
Nov 1, 2003
Messages
128
Re: '74 Johnson 50 wont idle in water?

I believe you're supposed to set the idle mix in real water also?
 
tashasdaddy

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: '74 Johnson 50 wont idle in water?

not idle mixture!!! idle speed is what needs to be set. set the idle at 1000 rpms on muffs. then put the boat in the water, and fine tune the idle speed, so that the motor continues to run, with the motor in gear. as Mike said, muffs no back pressure on exhaust.
 
M

melvino

Cadet
Joined
Sep 25, 2009
Messages
12
Re: '74 Johnson 50 wont idle in water?

Thanks tashasdaddy! I guess my question now is do I adjust the idle with the screws on the carbs or do I make an adjustment on the throttle control cable?
 
W

willib0731

Cadet
Joined
Aug 8, 2012
Messages
14
Re: '74 Johnson 50 wont idle in water?

melvino said:
Thanks tashasdaddy! I guess my question now is do I adjust the idle with the screws on the carbs or do I make an adjustment on the throttle control cable?
Click to expand...

Adjust on the motor for your basic settings. Only adjust your cable if the cable is way messed up. There is a balance you will need to find.
 
You must log in or register to reply here.
Top