Hi all, I'm brand new to this forum but hope that someone on here can assist with a problem I have with my 1981 Johnson 70HP SeaHorse (LoopCharge) outboard.
I've reviewed the previous posts on this same problem and have taken the advice offered in them but cannot cure the problem.
As a starting point I should let readers know something about the motor. I have only just purchased the boat / motor and the previous owner disclosed the following problems to me. As I have over 20 years experience (though no formal training) in repairing / maintaining all things mechainical (cars, motorbikes, lawnmowers, chainsaw, etc. etc. etc.) I figured I can probably fix this beast. The previous owner had run out of time, patience and money attempting to find a solution though!
He has had the carbs fully stripped, cleaned and re-fitted by a reputable Johnson Dealership in Melbourne (Australia). This failed to fix the problem. Then he (they) moved their attention to the coils...one was replaced as it had a slightly reduced output....no cure. The plugs were replaced....no cure...the engine wiring harness was completely replaced....you guessed it no cure. Fuel lines and tank replaced...no cure. Prior to any of this work compressions were tested and found to be O.K. in all three cylinders. After all of this he / they were no closer to fixing the below problem and so he sold the boat....now the problemsa are mine.
So what exactly is the problem.....well there are 2 to be exact.
The outboard starts just fine, it idles ok on initial start up using the fast idle lever to start. When I try to put in gear and accelerate it stalls, on attempting to re-start it does so without any hesitation only this time around it will rev to about 2000 rpm. The only way I can return the motor to an idle is by manually operating the linkage between the cable and the carbies (the large alloy one bolted to the engine housing). This will successfully resolve the issue until on this occassion but will return each and every time I go through the start up - put in gear / accelerate routine.
My diagnosis of this problem is that the cable is either stretched (but disconnecting the cable from the linkage doesn't fix the problem so I'm tippint the cable is not at fault) or the arm is "binding" on the engine housing for some reason. As this arm also operates the ignition timing set-up in the flywheel it could also be something up there causing the problem. BTW the linkage / arm which is failing to fully return to its point of origin is lightly spring loaded to return but runs out of "spring" about halfway back...should the cable then pull it back home? A previous thread pointed to the cable being responsible for the same problem on another motor, however no matter what I do to adjust my cable the problem won't go away. A point worth noting here is that the cables appear to be in good condtion (externally) and all fittings are clean and in good condition. Of course it may be that the following problem (or more so the cure for the following problem) ends up fixing this issue....
Anyway after that comes a much more sinister problem.....
When the motor is put into gear it stalls, I can get it to run (in gear) by adjusting the idle but no matter what it will still stall and / or bog down when I accelerate, only once have I managed to get the motor up to full speed and that was after about 30 minutes of stall / start / adjustment....it didn't last though it stopped when I slowed to about half throttle.
Today I have pulled the spark plugs and checked the compressions, top cylinder 120, middle 120, bottom 130. At idle all three cylinders are firing.
Suspecting the carbs may have still been a problem (as all previous threads pointed to them being the problem) I have today pulled them off. They were pristine inside and out, confirming the previous owners account. While I was in the area I also pulled the reed (leaf) valve mounting plate and blocks out to find they are in perfect (visual) condition with no curvature of the reeds or any other issues (I had suspected that maybe fuel delivery was an issue due to insufficient vacuum in the crankcase). Anyway now I'm at a bit of a loss as to what is wrong with this motor...it has compression, spark and fuel but just won't run properly. I suspect that it may still be carbies (fuel / air mixture) but as yet don't have a manual (one is on its way from the U.S. to me but won't be here for another week or so). I'm led to believe that fuel air mix is pre-set by the size of the jets in these carbies rather than by screw adjustment....can anyone clarify this for me? If they are pre-set (non-adjustable) then there's not much can be done there...if there not then if anyone can provide me with a quick "how to" that would be great (likewise on a "sync" procedure.
If that fails then I will check the timing and will have to check the output from the stator...or anything else anyone can suggest....I want my boat on the water not on the trailer! the motor is worth saving....everything is like new on it!....it just does nothing to get me where I want to be!
Thanks in advance for any assistance you can offer, hopefully I'll be singing your praises for years to come!
Richard.
P.S. I apoligise for the long post but wanted to provide as much information as possible.
I've reviewed the previous posts on this same problem and have taken the advice offered in them but cannot cure the problem.
As a starting point I should let readers know something about the motor. I have only just purchased the boat / motor and the previous owner disclosed the following problems to me. As I have over 20 years experience (though no formal training) in repairing / maintaining all things mechainical (cars, motorbikes, lawnmowers, chainsaw, etc. etc. etc.) I figured I can probably fix this beast. The previous owner had run out of time, patience and money attempting to find a solution though!
He has had the carbs fully stripped, cleaned and re-fitted by a reputable Johnson Dealership in Melbourne (Australia). This failed to fix the problem. Then he (they) moved their attention to the coils...one was replaced as it had a slightly reduced output....no cure. The plugs were replaced....no cure...the engine wiring harness was completely replaced....you guessed it no cure. Fuel lines and tank replaced...no cure. Prior to any of this work compressions were tested and found to be O.K. in all three cylinders. After all of this he / they were no closer to fixing the below problem and so he sold the boat....now the problemsa are mine.
So what exactly is the problem.....well there are 2 to be exact.
The outboard starts just fine, it idles ok on initial start up using the fast idle lever to start. When I try to put in gear and accelerate it stalls, on attempting to re-start it does so without any hesitation only this time around it will rev to about 2000 rpm. The only way I can return the motor to an idle is by manually operating the linkage between the cable and the carbies (the large alloy one bolted to the engine housing). This will successfully resolve the issue until on this occassion but will return each and every time I go through the start up - put in gear / accelerate routine.
My diagnosis of this problem is that the cable is either stretched (but disconnecting the cable from the linkage doesn't fix the problem so I'm tippint the cable is not at fault) or the arm is "binding" on the engine housing for some reason. As this arm also operates the ignition timing set-up in the flywheel it could also be something up there causing the problem. BTW the linkage / arm which is failing to fully return to its point of origin is lightly spring loaded to return but runs out of "spring" about halfway back...should the cable then pull it back home? A previous thread pointed to the cable being responsible for the same problem on another motor, however no matter what I do to adjust my cable the problem won't go away. A point worth noting here is that the cables appear to be in good condtion (externally) and all fittings are clean and in good condition. Of course it may be that the following problem (or more so the cure for the following problem) ends up fixing this issue....
Anyway after that comes a much more sinister problem.....
When the motor is put into gear it stalls, I can get it to run (in gear) by adjusting the idle but no matter what it will still stall and / or bog down when I accelerate, only once have I managed to get the motor up to full speed and that was after about 30 minutes of stall / start / adjustment....it didn't last though it stopped when I slowed to about half throttle.
Today I have pulled the spark plugs and checked the compressions, top cylinder 120, middle 120, bottom 130. At idle all three cylinders are firing.
Suspecting the carbs may have still been a problem (as all previous threads pointed to them being the problem) I have today pulled them off. They were pristine inside and out, confirming the previous owners account. While I was in the area I also pulled the reed (leaf) valve mounting plate and blocks out to find they are in perfect (visual) condition with no curvature of the reeds or any other issues (I had suspected that maybe fuel delivery was an issue due to insufficient vacuum in the crankcase). Anyway now I'm at a bit of a loss as to what is wrong with this motor...it has compression, spark and fuel but just won't run properly. I suspect that it may still be carbies (fuel / air mixture) but as yet don't have a manual (one is on its way from the U.S. to me but won't be here for another week or so). I'm led to believe that fuel air mix is pre-set by the size of the jets in these carbies rather than by screw adjustment....can anyone clarify this for me? If they are pre-set (non-adjustable) then there's not much can be done there...if there not then if anyone can provide me with a quick "how to" that would be great (likewise on a "sync" procedure.
If that fails then I will check the timing and will have to check the output from the stator...or anything else anyone can suggest....I want my boat on the water not on the trailer! the motor is worth saving....everything is like new on it!....it just does nothing to get me where I want to be!
Thanks in advance for any assistance you can offer, hopefully I'll be singing your praises for years to come!
Richard.
P.S. I apoligise for the long post but wanted to provide as much information as possible.