74 Johnson 70hp Help

longdraw

Cadet
Joined
Apr 21, 2007
Messages
8
Motor starts and runs very well off the hose but everytime I put it in the water it want's to staul out when put in gear. If I can get it moving without it stauling out it will roll at a slow cruise speed then staul if I adjust the throddle up or down at all. Frustrating stuff. This is my first boat, and don't have much familiarity with boat motors. I have been trying to familiarize myself with the motor as much as possible. Given the scenario it makes sense that this would be the result of an easily diagnosable problem by someone with experience.

Any and all help is much appreciated.

Jon
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 74 Johnson 70hp Help

i couldn't get to the link either. welcome to iboats. when you put it in the water there is back pressure on the exhaust, thus the idle needs to be turned up. in the water it should idle in gear at 650 to 700 rpms. it will then run around 800-850 on the muffs. do not rev higher than1500 rpms on muffs. here are some carb control adjustment that work well.

select the type control you have. http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=28;gtid=818798;gpid=818802
 

longdraw

Cadet
Joined
Apr 21, 2007
Messages
8
Re: 74 Johnson 70hp Help

Thanks for all of the help guys, here's another ???...
How do I measure the RPMs if I dont already have a gauge in the boat?
 

Rudy Brown

Petty Officer 1st Class
Joined
Apr 3, 2005
Messages
289
Re: 74 Johnson 70hp Help

Thanks for all of the help guys, here's another ???...
How do I measure the RPMs if I dont already have a gauge in the boat?

Got to have a tach. Only way to know. A cheap, but effective tach. Try tiny tach dot com.
 
Top