Help Please Help, 76 Johnson 15 Hp Elec Start

[duckhunt84]

I purchased a used 76 johnson 15 horse a week ago and watched it run in a barrel before buying. strapped it onto my 14 foot boat and it starts and idles great, but thats it. I try to crank throttle and it does not increase speed or rpms. I took to a boat shop this mourning and he said the teeth in tiller handle are lined up properly, and all functions of throttle are working correctly. After leaving i replaced the spark plugs, and looked at choke carefully to make sure it was fully disengaged. I just got off the water and its doing the same thing. Will not rev up. I can only go at a fast idle at best. Is this a carb issue?

 

[tashasdaddy]

Re: Help Please Help, 76 Johnson 15 Hp Elec Start

is the throttle timing plate moving (under the flywheel) advancing the timing. are the throttle plates opening and closing, not the choke plate? have checked compression and spark both cylinders?

 

[duckhunt84]

Re: Help Please Help, 76 Johnson 15 Hp Elec Start

It sounds like I better have someone take another look. When the marina took a look at it they were twisting the throttle and looking at all of the linkage (including under the flywheel) and said it appeared to be functioning. I have checked spark and that is great. I have not checked compression. If compression is good, I might have to take it back and get these throttle plates inspected you are mentioning. The only other thing I can think of is carb related? Sorry if I sound unexperienced. This is my first outboard.

 

[duckhunt84]

Re: Help Please Help, 76 Johnson 15 Hp Elec Start

Is there anything else I can check before taking it in?

 

[tashasdaddy]

Re: Help Please Help, 76 Johnson 15 Hp Elec Start

well if they looked under flywheel, while check the linkage, they check the timing plate. check the compression. if it is good then you may need to have someone pull the flywheel, and see if the woodruff key is sheared, this would throw timing off, and it would not start, but would have good spark.

 

[duckhunt84]

Re: Help Please Help, 76 Johnson 15 Hp Elec Start

thanks for the help tashasdaddy. I am going to check the compression first like you say. That woodruff key should be ok if the engine starts..correct. Everything seems to idle and run fine, but just wont throttle up? So would you say that you are leaning more towards a timing issue then carb?

Thanks again for your replies!

 

[duckhunt84]

Re: Help Please Help, 76 Johnson 15 Hp Elec Start

I checked compression, and its pretty good. Spark on both cylinders is very strong. Once I got the flywheel off I started to take apart carb and it looks pretty gummed up. I think this will be the problem, and if not needs to be cleaned anyay. I am going to start there, and then try and figure out the link and sinc process.

 

[duckhunt84]

Re: Help Please Help, 76 Johnson 15 Hp Elec Start

ok...I got the motor taken apart and inspected. The shop took off flywheel to get carb off. Cleaned it. Saw that there was no high speed jet in the carb? Installed this, link n sinc, and put back together. I got it on the water last night and it reved higher, but would almost plane my 14 foot boat. It seems like a 15hpmotor should do better? Not sure if i was at full potential. Then, after 10 mins, motor dropped back down to how it was before. Wouldnt go past fast idle. I pulled plugs and one is a lot dirtier then the other?? Should I call this shop back for another $80 service, or is something ringing a bell to one of you boat doctors?? Please help, I'm missing my duck season!!

 

[duckhunt84]

Re: Help Please Help, 76 Johnson 15 Hp Elec Start

anyone............?