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Random Quote: If you try to make it idiot-proof, some one will just come up with a better idiot!
Replaced my filters and the engine still konks out after running about 30 minutes once I go over 3500rpm's. Fuel vent seems fine and she starts up with no problems. It appears that it will run fine under 3000rpm's. I'm pretty sure the problem is the "new" gas with the ethenol added. The owner of my dock said his 25hp "Rude" died due to the "new" gas as well as 3 other boats at the dock. Talking around it sounds like boats are being "picked-off" one by one around here. Anyone here have an answer to correct this?
Verify the problem. You say the fuel vent "seems" fine but you have to know for sure. Otherwise you may be chasing your tail.
Get a small fuel tank and fill it with the same fuel you are using now. Operate the motor and see if the problem remains or goes away. If it goes away that will tell you the problem is with your fuel supply system. If it remains, it could be the fuel or something amiss with the motor itself.
If you are able to operate for 30 minutes at a time with E10 fuel I am betting that it is not related to the new fuel.
Well, I can't speak for your engine or situation, but I you guarantee that just about every other boat problem for the next two years will be because of ethanol.. It the problem is not because of Ethanol, then people will probably blame Bush.
If you're getting knocking happening, that is usually an indication of poor fuel delivery at the carbs.. Since it is above a specific RPM range, it sounds like a secondary on the carbs or something like that...
__________________ - Chris
Guess What?? I got a Fever.. And the only prescription is.. MORE COWBELL!
-2011 Blue Wave 2400 Pure Bay / Yamaha F300 4.2 with Command Link Plus
-2003 Sea Fox 195 Bayfisher - Mercury 125 Saltwater Classic (Sold)
-1994 Wellcraft V-20 Step Lift (Sold)
Pre season I ran into serious issues with my new boat. E10 was mixed with MTBE and it did the phase separation thing in the tank. I manually drained the tank, fuel lines, VST tank on the yamaha, replaced racors and then added a full tank of E10. No problems after going through 60 or so gallons.
What I pulled out of the tank was disgusting. I pulled out 23 gallons of good gas I used in my jeep and mower, ~1 gallon of alcohol (smelled like rubbing alcohol) and 1 gallon of water. Lucky for me there was only 25 gallons (in a 126 gallon tank) to deal with.
Had I not drained everything I can only imagine the probelms I would have run into.
I probably have at least 30 gallons of old fuel and 35-40 gallons of new fuel. I checked the plugs and they look fine. The vent is not an issue. The one time I did have vent problems I would hear a rush of air when I opened the fuel cap. This is not happening. But now that I think of it,to get the engine going again I pump up the bulb which is soft to begin with. Someone at the dock did say that there is an additive you can use until the "old" gas is gone. I might give that a try.
Thanks for the replies! I'll be still open for more suggestions or ideas.
Well, I can't speak for your engine or situation, but I you guarantee that just about every other boat problem for the next two years will be because of ethanol.. It the problem is not because of Ethanol, then people will probably blame Bush.
If you're getting knocking happening, that is usually an indication of poor fuel delivery at the carbs.. Since it is above a specific RPM range, it sounds like a secondary on the carbs or something like that...
I added an 8oz bottle of "Startron" made by Starbrite. A enzyme fuel additive that the local marine store is selling. Everyone in town is sold out and I was able to get the last two! The engine did stall on me once today but it seems it's much better. Less smoke too. I might have to use this for a while and live with the occasional stalling until I use up the gas mixture I have. In the meantime today I saw several boats being towed in including this one below! My bet is the fuel...
i had a half gal of eth/h2o seperate in a 6gal tank that was bone dry before e10. motor wouldnt stay running after elimating all the tough stuff i tried squeezing a bulb or 2 from tank and there it was, a 1/2gal of the mix. so its not all hype
Did you move to the Racor with the clear bowl? I was having an ethanol nightmare-- changed the primer bulb, gas lines, blew out the vents, new pickups on the tank--nothing worked for long until I got the better racor.
I have to endorse Startron. I was having all kinds of idling problems until I put a bottle of that stuff in the problem tank. After a couple of days the problems were gone. Just make sure you have spare filters on board because they will become clogged. I’m on my second set on both engines.
Dave
I had all those problems too. I ended up replacing/cleaning everything in the fuel system. You may want to change your fuel pump. My Diaprmas had crap all over them. Also, I switched to the "yamaha" 10 micron filter. It seems to have better capacity and lasts longer than the racor cartidge.
I installed the Yammi 10 micron setup on a 1979 boat that has all old stuff in the fuel system. The new & old fuels were mixed & 200+ gallons have been used since the new filter. Zero problems.
You say you have 30 gals of old fuel and 30-40 gals of new fuel?!? It is known that ethanol and MTBE do not play well together, and it was recommended to have no more than a 4:1 ratio of E10:MTBE fuel (i.e. make sure you have less than a quarter tank of old gas before filling w/ E10).
You probably had a reaction in your tank b/c you had too much MTBE fuel, and thus the 1st thing you should do is drain your fuel tank.
HS, I don't know if it fits, but the entire Yammie assembly was only $40 with a filter. It's good enough for 2 engines.
I had a 1970's jobber that I replaced with the Yammie & all of the fittings were the same. It took about 10 minutes. We have three boats, all inboards, using them & no fuel problems to date.
Now what? Ethenol headache! 
