81 Johnson 35 HP problems

[swampdrummer]

Picked up a used boat for cheap and it has a johnson 35 on it. Trying to get it running.
It has been sitting for a "while" Compression is 100/105 cold. Just rebuilt the carb, it actually looked pretty good.
New gas tank, new gas lines and fittings
I can get the motor to start but it either dies on its own in just a few seconds or it will die when I try and apply gas. The fuel bulb isn't staying real hard, after it starts, I can get maybe a half a squeeze before it gets hard again. Then I can choke it, pull it once. Push the choke back in and pull one more time and it will generally fire. Then die. I did get it to rev up once before I quit for the day......
I'm thinking fuel pump but wanted to run it thru the forum before heading that way.
Model # J35RLCIG
Serial # E5542443
Thanks much!
Brad

 

[HighTrim]

Re: 81 Johnson 35 HP problems

It does sound like your fuel pump Brad, or fuel delivery related anyways.

If you remove your fuel line what does the fuel supply look like while cranking? Have you tried spraying pre mix fuel into the carb throat, does that help? Also what is your starting procedure, step by step?

Were the carbs floats properly set? Have you tried checking spark just for fun?

You could also try getting a vacuum gauge and installing it inline on the fuel hose before the engine, along with a clear section of hose. Take it for a spin, noting the readings and monitor the fuel flow through the clear hose.

Findings:

-Vacuum of less than 2 inches and air bubbles in the clear hose indicates an airleak into the fuel system
-No air bubbles and less than 2 inches indicates a bad fuel pump
-Vacuum over 4 inches indicates a restriction.

Sample gauge

"http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=STRK%3AMEBTOX%3AIT&viewitem=&item=4610113711&_trksid=p3984.cTODAY.m238.lVI"

 

[swampdrummer]

Re: 81 Johnson 35 HP problems

Thanks High Trim.
I have not pulled the fuel line as of yet. Just started working on this motor this afternoon. I know I have fuel to at least the fuel pump as it had a small leak that was fixed by pulling the face off and cleaning up the gasket and putting it back together. Haven't checked further than that.
The carb float is set correctly. I have not tried spraying pre mix into the carb. Mainly because it won't stay running long enough to do that! LOL
Kind of winging it on the starting procedures. Pull choke. throttle just a hair past slow. Couple of pulls on starter rope. Push choke in and pull. It is usually starting in two or three pulls. But then dies quickly. 10-30 seconds....

I did check spark. Good there.
Will try and find a vacum guage tommorow as well.
Thanks again!
Brad

 

[tashasdaddy]

Re: 81 Johnson 35 HP problems

the motor has and automatic stop for the throttle, when in neutral. turn the throttle as far as it will go. don't worry what the pointer says. did you remove the low and high speed jets, replace the needle seat and needle and use a rebuild kit. if not could be clogged, even the float needle could be sticking.

 

[HighTrim]

Re: 81 Johnson 35 HP problems

Also I assume you have fresh fuel in it?

http://forums.iboats.com/showthread.php?t=225510

 

[swampdrummer]

Re: 81 Johnson 35 HP problems

Brand new fresh fuel in a brand new tank, hoses and fittings.....
I pulled and cleaned both low and high speed jets. Replaced the float needle. Used a rebuild kit . Pretty sure I got all of what little bit of junk was in there. Flashlight and pipe cleaners thru all orifices etc etc...
Not sure about the nuetral rev limiter as the throttle seems to advance the same distance in nuetral and in gear....
Thanks

 

[tashasdaddy]

Re: 81 Johnson 35 HP problems

i like to use a squeeze bottle ( the one that comes with oxi clean) like an old mustard, kethcup bottle. put premix in it, and put a little directly into carb. then give a couple of good pulls, should start. then some more premix. if it keeps running with the squirts, you have fuel problem.

 

[swampdrummer]

Re: 81 Johnson 35 HP problems

Thanks guys,
Went out this afternoon and discovered a fuel leak coming from the back gasket on the fuel pump. Need to get that taken care of before I go much further. May be the problem, Maybe not but fuel leaking on the block ain't good!

 

[HighTrim]

Re: 81 Johnson 35 HP problems

Very well could be. Good luck.

 

[swampdrummer]

Re: 81 Johnson 35 HP problems

Rebuilt the fuel pump this morning and pulled on the starter cord for a while with about the same results.......
Decided to pull the carb and take a look again. Found fibers from the pipe cleaners that I used to clean the carb the first time around in several orifices.. Cleaned everything again and put the carb back on. First pull and the motor fires right up! WOOHOO! Ran it for about 20 minutes on the hose and everything seems to be in fine shape. Lesson learned.... No more pipe cleaners in outboard carbs!
Thanks guys!

Brad

 

[swampdrummer]

Re: 81 Johnson 35 HP problems

Just an update.
Finally got the boat in the water today for a "real" test run and I can say. She runs like a scalded ape!
Still a few minor problems to address, sticky throttle linkage and probably a dolfin of some sort to fight bad bow rise but all in all. A succesfull test.
Thanks guys!