threeCs Loc: Allen Texas

To all of the DIYs

I have a 1988 Johnson outboard engine that I have been having fuel problems on. What is in this pertains only to the motor that I have but principle of how 2 cycle engines work applies to most brands.

I started using a 6 gallon portable tank several years ago because the 20 gallon tank on the boat was just more fuel that I could use in a reasonable time. I had removed the VRO several years ago also because it was not working correctly. Could not trust the VRO to give the proper mix. When I mix the oil and gas I know the ratio is correct.

The trouble started when I had to purchase a new portable tank. It was a Attwood model. It had the new EPA mandated connection. I found the connection to be hard to make each time, sometime it made good connection and other times I failed to get the two sections mated correctly. This cause me to have a fuel distribution system problem.

I purchased a new set of connections like the original Johnson used but they proved to be defective also. When primer bulb was squeezed they would allow air into the system. I then purchased a brass pipe to hose coupling and removed the quick disconnect fitting. I now do not disconnect the tank to refill it but add fuel from another container. I then had a positive connection to my supply tank.

The motor would run on low rpm fairly well but at high rpm it starved for fuel so my problem continued.

Gas with ethanol is not your friend in any way for several reasons. 1. collect moisture, 2. not good for hoses and gaskets. With this in mind I decided to replace all the fuel lines. I used the internet for a source of information and realizing you have to be careful of information found on the internet I was cautious.

Automobile fuel lines are not UV protected and will crack with time when exposed to the sun. Found a couple of articles on the Attwood fuel line. The Attwood line is UV protected but in order to make the outer covering UV safe the ethanol attacks it. To solve this problem they put a liner inside the hose that is ethanol tolerant. As a results you must be real careful to get the fitting inserted inside the lining. and even then the lining with time will fail and clog the system. I elected to go to the automobile type hose.. On my pontoon boat the fuel line has very little exposure.

Even with new hoses I still had fuel distribution woes. I looked at installing a electric fuel pump instead of the pulse operated standard fuel pump. Several warned against it because if hose burst fuel would be sprayed everywhere. I decided to do it anyway and selected the lowest pressure pump I could find, 2.5 to 6 lbs, and wired it into the run switch on the ignition switch.

With the electric fuel pump I had fuel pressure at the carburetors inputs.. I had removed and cleaned the carburetors when this all started. This model has fixed jets so cleaning is fairly easy. Sea Foam soaking and air hose. Motor now has problems idling. and still will not perform at high rpm.

Several articles on internet said everyone wanted to blame reeds and in fact it was very seldom reeds but carburetors. At this point I decided to ignore that piece of information. I removed the carburetors and the intake manifold so I could inspect the reeds. This motor has 6 reeds each with 3 fingers. When you look at reeds you should not see any light when looking toward a light source. 12 of the 18 fingers I could see light meaning they were not seating correctly.
I ordered and installed 6 new reeds and they seated without light showing. Put parts back on motor but my problems were not over. It did not idle properly but did perform at higher rpm. I noticed that I had fuel slick with motor was idling, may have had at higher rpm but did not check.

I became suspicion of the electric fuel pump pressure overriding the carburetor float system. I took the electric fuel pump off and put the pulse type back on. Problem solved, idles good and runs at high rpm.

I guess if you would install a fuel demand valve after fuel pump, the electric pump could work.

Here is another piece of information that I ran across in this process. If pulse type fuel pump is not working properly be sure to check for plugged pulse limiter fitting. This is the fitting that screws into the block of engine and pulse line to fuel pump in connected. This would prevent pulse form operating fuel pump.

Sometime I am a slow learner but will evidently get there, hopefully.

plumbob Loc: New Windsor Maryland

Thanks 3 C's it was like reading a page out of my 9hp Yamaha a few years back. Went through it all both on land and water. Wont bore you with the details so similar to your story. Bottom line it was the interior hose had broken down and lit bits of hose messed up the carb.

All my gray and white hair has grown back now after many pulling's.

Able Man Loc: North Coast (Cleveland, Ohio)

Thanks, threeC's; it does always seem like, if it ain't 1 thing, it's 15 others. The thought came to me, that 1 way to get around the UV Ray exposure, might be to clean the outside of that portion of the fuel line, that is exposed to the sun, with fingernail polish remover (unless you got some leftover acetone); then wrap just that part of the line / yellow electric tape. No longer exposed to the UV Rays.

Mister twister Loc: Foxworth,Ms.

Mid and late 80’s Johnson’s and evinrude shad a well hidden problem in their choke systems. Even trained eyes scratched their heads. These chokes worked but they had a glitch. The hp was there but the system held back like a governor on older autos. The flooding of fuel was the choke that couldn’t be adjusted.