I have a question for anyone that can help... I have an early 80's eldocraft bassboat with 150hp Mercury. I bought the boat about a year ago and was told the engine had an overhaul on it was good to go. The boat has never started on its own (so i have to use starting fluid to get it started) but once it's started it runs like a top. For a long time the engine would cut out when i got on the throttle...just bog down, then pick back up, then bog down, and sometimes not run at all. I could spray the starting fluid into it and it'd run again for a good while, then do it again. Today, out on the water, i believe we diagnosed the problem... As we were runnin across the water, my brother was laying across the deck pumping the fuel bulb the entire time and we made it all the way back... so I know somewhere there's a problem there. When you pump, it does not immediately expand back to its usual size, but stays sucked in, and takes a while to expand.... Anyways...as long as he was actively pumping the bulb, we made it back ok. Does anyone have any ideas? Is is sucking in air somewhere possibly? Or does something sound clogged? Thank yall very much for any suggestions!

You might try replacing the anti-siphon valve on your gas tank.I think they run about ten bucks so this may be a cheap place to start.I was having similar problems and this fixed my problem.

Is the tank built in? Air vent clogged/open (due to mainly dirt dabbers.)

I don't know much about boats but I thought I had a fuel problem. Had the same symptoms except the collapsed fuel bulb. Turned out to be a bad ground.

I've experienced the same problem with my 79 Glastron/140 Johnson. How do check for a bad ground? Occasionally the engine won't start, won't even turn over, but its sporadic.

I've experienced the same problem with my 79 Glastron/140 Johnson. How do check for a bad ground? Occasionally the engine won't start, won't even turn over, but its sporadic.

You need to look at your fuel pump......I wouldn't be spraying starting fluid to start....it washes the cylinders clean and you can get scoring or worse damage. It could also be fuel tank related as mentioned above. I would not be running the boat like it is....you are obviously having a fuel delivery problem and if you are not getting fuel to a cylinder(cutting out) you are also not getting oil!!! I would also want the carbs to be looked at as well. A stuck needle will cause the same symtoms, hard starting and cutting out. Take in for service or buy a manual.

real good advice

Thanks a lot scanos! I appreciate all the advice!

Bad needles will cause the motor to surge which is one of your symptoms but, the collapsed bulb tells me to go with the anti-siphon valve all the way. Also, I second what Scanos says about spraying fluid into the intakes. Breifly spraying carb cleaner to test is OK but, running on anything if you have no oil mixed is not good.

bassman22, replace your bulb, you have a bad check valve, this will cost about $10 to $12 to fix, also if you have two tanks, besure the switch valve is turn all the way open to the tank you are using at the time, mine hang a little sometimes, won't notice till your on plane and the engine sucking fuel, then boggs down because of lack of fuel. Hope this helps, let us know if it cured the problem.

if the bulb isnt the problem, replace your fuel lines. SOunds like one is collapsing.(they get soft and when the motor pulls the fuel thru the hose it creates a vacuum of sorts- and if the fuel line is soft(worn out) it will collapse )

I have a similar type problem on a mid 80's model Johnson 175hp. Everything goes fine until I hit about 36-39 mph, then it starts to bog down. If I back off the gas real quick and then give it gas a time or two while I am still on plane it keeps on going.

Does this sound like the same thing as discussed above or not. I have changed the sparks plugs, but have tried nothing else.

I would add that the first thing I would do is run the boat on a test tank(alternative fuel tank) this will rule out everything up to your fuel pump if it still runs bad. If it runs good you know it is fuel tank, anti-syphon or fuel line related. You can buy a 3 gallon tempo fuel tank pretty cheap....just make sure you open the vent all the way.

where is the anti-siphon valve?