Forum Index
The Boater's Guide to Information, Education & Scuttlebutt...
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

1977 johnson no power under load

 
Post new topic   Reply to topic     Forum Index -> Join our Boaters Community!!!
View previous topic :: View next topic  
Author Message
gizmolvr



Joined: 25 Apr 2008
Posts: 1

PostPosted: Fri Apr 25, 2008 5:04 pm    Post subject: 1977 johnson no power under load Reply with quote

have a 77 johnson 140 installed on an 18' center console. Took it out yesterday and the boat would not go over 10mph and the rpms would not go over 3500. Once in a while the motor would "kick in" and the rpms would go up and the boat would start accelerating as it should and you could feel the power was there. I tried 3 different props but since it would occasionally "kick in" i dont think that is the issue. Compression is good. I am assuming that I am not getting spark to one of the cylinders or the power pack is bad. Any ideas?
Back to top
View user's profile Send private message
MikeW
Senior Member


Joined: 01 May 2006
Posts: 680

PostPosted: Mon Apr 28, 2008 7:24 am    Post subject: 1977 johnson no power under load Reply with quote

I would fire up the engine and pull the plug wires off one at a time to see what cylinder is not firing. If you have separate coils, I would switch them and see if the problem switches to another cylinder.
Back to top
View user's profile Send private message Send e-mail
boatScotty
Senior Member


Joined: 07 Nov 2006
Posts: 229
Location: Pacific Northwest

PostPosted: Mon Apr 28, 2008 7:30 am    Post subject: 1977 johnson no power under load Reply with quote

First guess is that you are indeed not getting consistant firing due to misfiring to one cylinder.

Check plugs, wire (test for firing) first. Then Powerpack.
You are indeed on the right path for diagnosis.

To understand the parts and their roles:
http://www.outboardignition.com/
_________________
Boat Scotty

Marine Tech.
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic     Forum Index -> Join our Boaters Community!!! All times are GMT - 7 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum