Engine Problems?

[newlights]

Ok guys I want to describe whats up and get your al;s opinions. I have an 85 horse Yamaha engine 1991. I just had all three carbs rebuilt and water pump replaced cost me about $500 in mechanic fees, took it out Friday night, Sat, and Sun.

While turning around at high speed on Sunday the boat lost power and idle down and died as if I had ran out of gas. I assumed this was the case since I had been out a while and switched tanks. Could not get the boat started forever got it flooded when we switched b/c of a stupid firiend who would stop pumping the bulb even after I had it initially started.
Anyway once we finally got it started and I got down the lake a bit at full speed it was like the Engine lost 35% or so of its power all of a sudden and slowed down and sounded different. Like it wasnt getting the gas or something. Bogged Down more or less. felt as if it were trying to work something through it. Then bam it came back full only to loose it agian a few sendonds later and continues back and forth. I brought it back down to idle, and started agian full speed going great for a bit then a repeat. Now it does it nearly every time it will run great untill I hit a certain speed and then it starts to give me those intermitent issues.

On friday night I gps'ed and was getting 23 MPH with one passenger other than myself Yesterday I was getting 19 with 5 people total on board. So the motor was going strong at least for a while. Any ideas? The mechanic said it might still need adjusting. but since it did so well I doubt thats it. COuld it be air getting into the fuel line? Like a faulty siphon?

[Parasympathetic]

Check the vents on your gas tanks. Fuel filter? Were you having a problem before that caused you to rebuild the carbs?
After the rebuild, did you start with new gas.

[newlights]

THe engine had sat for two years I bought it non working. I did have empty tanks and fileld them up with fresh gas and oil correct 50:1 ratio and I added a fuel stabalizer to the tanks as well.

[trott46]

I have worked on a 1992 25 horse yamaha with similar issues. Person before me rebuilt the carb. I had found that when they had rebuilt the carb the fuel bowl gasket was just a little large and was catching the float in the carb. Trimmed the the gasket down and all is well.

[slingshot]

Are you saying that the gas is 2 years old or that you recently filled tanks? I'd try a brand new tank w/ a new fuel line and bulb. It sounds like a fuel starvation problem. Check your compression in case you've got a low cylinder that's loading up on you.

[newlights]

The gas is fresh but in old tanks. I called the mechanic that rebuilt the carbs he saidit sounded like there was gunk or water in the fuel and advised me to take off the fuel filter and dump it and to take of the bottom of the carbs? and dumb taht if there was water it would collect in those places. I am takeing a friend of mine who is a ford car mechanic to help me take this stuff apart tomorrow we will know more then. I do know that as soon as I get a few extra bucks im getting a external sediment/water fuel filter for it to prevent this from happening agian.

[texaspontoon]

Man, I feel your pain. I just had to spend $400 to have my new Honda 150 flushed out because I put 3 cans of gas in my boat that were bad. (I should have never done that, but I was confident the gas was fine). I even had a seperate fuel water seperator, and the one that comes inside the engine. But he kept what was inside my motor (inside the Vapor separator tank) and it looked like a mixture of water and varnish. He had to drain and flush my tank. He gave me a new fuel additive called "Star Tron" that seems to have made a huge difference. One thing I learned that day, boats may glide accross water, but they run on good fuel, not water! Huge mistake on my part.

If everything else on your boat was running good, my guess is your tank had been sitting for two years and built up water and sludge from the new crap they put in the fuel.

It could also be that your fuel hoses do not have a good connection or are cracked etc (so they are sucking air, or not air tight enough to pull fuel through the line as your fuel pump is trying to do).

Good luck and let us all know how it came out!

[Bamby]

I have an older boat that I did a complete rebuild on. Anyway the fuel tank was old "probably original" and though I thoroughly flushed and cleaned the tank before reinstalling there was residue still fixed in the tank. You could see it in the opaque plastic as a person looked into the tank. All was well and the residue stayed fixed to the tank for quite some time until I had no choice and had to fuel with "ethanol laced fuel". All I can say as of that fueling I now have the cleanest whitest fuel tank anyone has ever seen. Ethanol is a solvent and a very good cleaner, fortunately I had installed a very good fuel / water separating filter and new fuel lines and non of the gunk made it to my engine. There is a chance your fresh fuel may have also performed a through cleaning also, but unfortunately maybe your gunk is now residing in your engines filter and float bowels. Hopefully draining the bowels and a filter change will have you on your way.

[newlights]

I hope so Tonight we will drain the filter and bowls, and are going to add some heet to the tanks to ensure there is no water.

[newlights]

That ray looks like it was a fun fight!!! I would love to fish out in the ocean!

[Parasympathetic]

CRICKIE !!!!!!

[newlights]

FIXED!!!!!! LOL it was really simply so simple I feel dumb for not noticing but so simple im very happy thats all it was. So I took my mechanic to the boat and we discover about the same time that the siphon hose had a crimp in it. It was too long and apparently as I made the turn before it started messing up, It crimped a little then when at ful throttle the suction of the engine for gas makes the hose nearly close causeing it to starve for fuel. we cut it and put the end back on and all was good up and down the lake she went full power no problems. He listened to the engine to make sure it sounded ok he said if it had water he would be able to hear the difference and nothing the toon ran great at ful speed agian !!!!!! I am sooooo happy!!!!

[Parasympathetic]

It always is the simple stuff that's causing the problem..............except of course when it's the complicated stuff.

Glad you got it working.