Outboard runs bad with fuel line connected

[rickymanonsen]

Hello all, my name is Ricky and I have my first boat and I feel like its been in the shop more that the water lol.

I'll get right to it.
Had the boat out 4 weeks ago and I have 2 attwood 6 gallon tanks.
After cruising around for a couple hours, my first tank ran out of gas. I switched tanks like I have done many times before and it really struggled to start back up. Finally got it cranked and got it in, the whole way back, it would only run at half throttle.

After getting the boat home, i went to flush it and still ran like crap. The weird thing is that if i disconnect the fuel line from the motor it purrs like a kitten using the fuel left in the carbs, as soon as i reconnect the fuel line to the motor, it almost instantly starts running like crap again. I have tested both fuel tanks and put a new fuel line and primer bulb(in the right direction).

it is currently in the shop now with a new fuel pump. The guy is working on it now i think is stumped, but will not admit it lol.

Could bad connectors to the motor and/or for the tank cause this problem? I really don't know what else to do.

1975 Galaxy 15' trihull 1979 johnson 85hp. boat ran great before this problem. thanks in advance for the help.

 

[graydonmcarthur]

did u check fuel filter?

 

[mdsmith62]

did you open the vent on the fuel tank

 

[rickymanonsen]

tank does not have a vent, has a click style cap like in your car. Have never had an issue with those particular tanks before. there is no filter.

link for tanks i have.
http://www.amazon.com/gp/product/B0053HOX4O?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s01

 

[hardwater fisherman]

Im not saying it is the problem but there is a filter screen at the fuel pump.

 

[oldboat1]

Fuel pump rebuild or replacement might do it. First thought when running a tank dry is that the engine sucked in debris or water, normally requiring carb cleaning/rebuilding. Presumably, the shop is running it on a shop tank to isolate issues. If fuel pump doesn't resolve it, would look to carb removal, draining/cleaning, and rebuild.

 

[racerone]

????------Fairly simple I think.---With the hose hooked up it could be a bad diaphragm in the pump flooding one cylinder.--Fuel would go right into the motor and not make it to the carburetors.-----Or you have a flooding carburetor allowing too much fuel into 2 cylinders.----With the hose disconnected the motor is running properly with the fuel that is in the carburetors until that runs out.

 

[F_R]

I would say there is a hole in the fuel pump diaphragm, except you say it is a new pump. But check it anyway. Remove the pump from the motor (hoses still attached) and give the primer bulb a squeeze. If gas squirts out the hole in the backside of the pump, that's the problem.

 

[Vic.S]

My guess is that one of the carb float needle valves is not closing properly so the carb is flooding......... disconnect the fuel line and it stops flooding and runs sweet until the carbs run dry.

Like Racerone says

 

[mdsmith62]

dose the same thing happen with both tanks

 

[rickymanonsen]

Something I left out was the grey foamy substance coming out of the prop exhaust as well.

 

[rickymanonsen]

Got the boat home from the crappy mechanic.He also told me the grey/brown foamy stuff coming out of the exhaust was lower end unit oil and that I need new prop seals for $1000 labor only, plus my carbs needed to be cleaned $284 labor and $50 a carb for kit. Pshhhhh, please.

He changed the fuel pump and charged me 6 hours labor for scratching his head.$500 wasted. He did tell me that i needed a new fuel line form the fuel pump T going to the upper carb as it had a crack in it.

I pulled the upper carb off myself and replaced the fuel line, and it fired right up. I still knew something was just a little off, but close. I then proceed to take to my original mechanic. which i should of done in the first place. He cleaned both carbs for $85 each, awesome!!! and it now runs perfect. He also told me that the grey/brown foamy stuff in my prop exhaust was unburnt fuel from the bad fuel pump, the diaphram had a tear in it and it was being sucked through the motor head which is supposed to create a vacumm for the fuel pump, and coming back out unburned through the exhaust.

Long of the short, all is fixed and running great again, all it needed was a new fuel line, fuel pump and carbs cleaned. Do not take your boat to "The Shop" in Pearland Texas. His name is Roy, and he liar and inexperienced. Had my boat for 3.5 weeks.