Ongoing caburetor issues '91 25 HP Johnson

[hschmidt13]

I had starting issues with my 25 hp johnson. Rebuilding the carburetor corrected the issue. I lost my source for pure gasoline and started using E10.After a couple weeks the fuel seperated and I had starting problems again. I changed the fuel and corrected the issue. The boat sat for a month or so and I again had issues with the fuel. I have changed the fuel and can start the engine, but it only runs while the bulb is being squeezed. I rebuilt the fuel pump when I rebuilt the carburetor a couple months ago. The tank, supply line, and bulb are all new. Does this sound like a carb or pump problem?

 

[bktheking]

Re: Ongoing caburetor issues '91 25 HP Johnson

Pump the bulb till hard, pull the line from the carb and place it into a container and start the motor, observe the fuel line for pumping. Or change the line going from the pump to the carb to clear gas line to see if it's pumping, the first idea is cheap!

 

[hschmidt13]

Re: Ongoing caburetor issues '91 25 HP Johnson

I pulled the carb today - it's apart and soaking over night. I had a lot of fine sediment and gelled ethanol in it. I have new tanks, new supply line and bulb, does a 91 Johnson need to have the fuel lines changed out to keep E10 from deteriorating the rubber? I've had this carb off and cleaned it three times this year. Is any one having major fuel problems with ethanol. Are there any good additives to keep the ethanol from seperating. Are plastic tanks more suseptable to water condensation? The boat is docked most of the year and is only run on the week ends so it sits most of the time. This is really frustrating.

 

[Willyclay]

Re: Ongoing caburetor issues '91 25 HP Johnson

Welcome to the iboats.com forum. The experts here, which I am not, can help you solve any issue with your boat, motor and trailer. While StarBrite and Stabil both offer fuel additives specifically for ethanol/gasoline blends, nothing is 100 percent. I use additives but still run my carb dry after each day's use. You probably should replace any fuel lines/hoses that are not alcohol resistant. Good luck!

 

[Dhadley]

Re: Ongoing caburetor issues '91 25 HP Johnson

Welcome to the E-10 era. The small debris and gel is what will tell you where the problem is coming from. Small black specs are either fuel line or from some other rubber part. The gel is from additives mixing with the ethanol and/or plastic. If you use more than one additive they could be forming the gel. If your motor is a premix model make sure you use a quality brand oil. Those using injection seem to have less geling issues. Those mixing seem to have less geling issues using a synthetic blend oil like XD50, Pennzoil Blend or the like.

You could be getting more than 10% ethanol. Get the $7.00 kit from Briggs & Straton and check. Make sure your fuel lines are the latest ones that are A-1/15 rated. Running your carbs "dry" (they aren't) can cause other issues but if doing that solves the current problem then it's something to consider.

Make sure you clean the carbs properly. We see a lot of people soaking the carb in gas or lacquer thinner. Soak them in carb cleaner and use OE kits to rebuild. Especially the needles need to be OE.

 

[robert graham]

Re: Ongoing caburetor issues '91 25 HP Johnson

Install fuel/water separator(Walmart $27) on the inside of your transom to stop most trash and water before it reaches your carbs. Use Sta-Bil Marine(Walmart $20/quart) all the time. Get rid of any automotive fuel lines and replace with marine fuel hoses. Check/dump/clean your fuel tank and start with fresh fuel. Once you get a this fuel issue squared away, you will eliminate most of your carb problems. Good Luck!

 

[psteurer]

Re: Ongoing caburetor issues '91 25 HP Johnson

Good advice from Dhadley. Based upon your infrequent use, it would be advisable to run some type of fuel stabilizer such as Stabil. I have a 1989 20hp and run mine maybe about every other weekend. I run my motor dry at the launch every time I am finished. It is safe to do this since this motor has 1 carburetor that feeds 2 cylinders. I have been running Sea Foam in my fuel mix and nothing else. I am not sure how good the Sea Foam is as a stabilzer but so I have not had any problems.

In this day of ethanol, the key is to try and keep your fuel fresh. I keep my vent cap closed on the fuel tank when not in use. I usually try to just have a gallon or less of fuel in the tank when I am done for the weekend. Then the next time I use the boat I fill the tank to the level of how much I think I will use for the weekend. Having a second fuel tank is helpful in that you can use all the old fuel in one tank and then start on the next tank.

 

[hschmidt13]

Re: Ongoing caburetor issues '91 25 HP Johnson

thanks for the great advise. I put the carb back on after cleaning it and the motor runs great. I've been researching fuel additives to slow the alcohol seperation and there is some controversy as to whether they work or not. The one thing I read that makes sense is to avoid additives with alchohol... it could increase the total content to over 10%. One article written by a chemical engineer said that if there was an additive that stopped phase seperation the gasoline companies would use it. Has anyone had any luck with the enzyme additives?