2000 Johnson 35 hp (3 cyl) - wont idle, wont start after warmed up

[larzw]

I am a rookie when it comes to boat motors, but I really want to fix this myself!

After sitting overnight the boat will start if you pull up the choke...

As soon as you put the choke down, it will stall unless you immediatly give it quite a bit of throttle. It will then run for a while, but seems to be a bit low on the top end RPM's...but still will not idle or even run at low speed without being choked.

If you run it for 20 minutes or so, and then shut it off it will not start until it sits for a while. Sometimes you dont have to shut it off...it will just start bogging down and then die.

I was thinking it was something with the carbs..but wanted another opinion before I spring for the carb rebuild kits. Is there an adjustment? Or something that needs to be cleaned out?



-Larry

 

[Haffiman]

Re: 2000 Johnson 35 hp (3 cyl) - wont idle, wont start after warmed up

If you still have the oil-mixer in operation, disconnect it and just mix 2% oil in the fuel. Your carbs might be clogged down by over oiling, clean them out.
Before starting any repairs, get confirmed that compression is up and even on all cylinders.

 

[daselbee]

Re: 2000 Johnson 35 hp (3 cyl) - wont idle, wont start after warmed up

I was working on one just last week...a 25hp, but essentially the same motor.

Please get compression readings and post back.

It sounds as if we have the same problem. I have pretty much decided that there must be something wrong with the crankcase seals because this motor is way way too easy to turn over by hand, yet the compression on all three is 90, 95, 80. That is surely adequate to at least get it running....

The only way I got it to idle was to set the idle timing to 6BTDC. That is 10 degrees off spec....should be 4ATDC.

It has no power at all...I have been thru everything, carbs, ignition, nothing left but crankcase pressure. Reeds do not appear to be leaking, because I see no gas spitting back out the carbs....so....

Please post your three compression readings.

 

[daselbee]

Re: 2000 Johnson 35 hp (3 cyl) - wont idle, wont start after warmed up

Bump to top.

Do you have those compression resdings yet?