Pontoon Boat & Deck Boat Forum

I took my toon down to the lake today for a shakedown run. Unloaded and started it but it kept dying and then I couldn't get it started. Oh yeah, its a 88spl Johnson two stroke. I couldn't get the primer bulb to pump up. You could kind of feel the fuel come into it but it wouldn't get as solid as it should. I loaded up and came back to the house. Good thing I only live a mile from the boat ramp and not an hour away. I would have been pretty upset but no big deal. Its and old boat and will have some bugs and quirks to work out. When I got home I messed with it for a bit and when I squeezed the primer bulb, I could hear air coming from the connection where the fuel line connects to the tank. When I disconnected it from the tank I couldn't hear the air. Im going to get another quick connect and see if that will work. Im thinking that is the reason I couldn't get it to run. I believe it was sucking air.

How does a fuel system work on an older two stroke? Do they have a fuel pump of some type? I know Yamaha jet skis have a pump on the carb but it don't really have enough pumping power to pull fuel to the carb so there is a pulse line from the crank case back to the tank and that pulse pressurizes the tank to help push the fuel. Also, my plastic boat tanks have a vent valve in the cap. Do these need to be open or closed when in use?

The fuel line and bulb has a check valve that only allows the fuel to go in one direction. I think the pumping action actually rids the system of air so the fuel pump can such the fuel into the carb.

The fuel pump is mounted on the engine block has a hole it that goes into the crankcase. As the pistons move, they put out air, which pulsates the rubber diaphragm in the fuel pump thus making it "suck" and "push" fuel to the carbs.

I usually keep a backup fuel line and bulb and two tiny clamps around, as they're often culprits to an engine not promptly starting. But last time I looked at WalMart, the universal fuel lines with the bulb were something like $40. Ouch!

So that is basically somewhat the same as a jetski setup only a ski setup has the pulse line to help push the fuel to the carb pump. Yeah I priced a complete fuel line and it was pretty price IMO but if you gotta have it...?... This one has a new primer bulb and it is on he right way. Im thinking my problem is either the male or female connector at the tank.

Darin wrote:I took my toon down to the lake today for a shakedown run. Unloaded and started it but it kept dying and then I couldn't get it started. Oh yeah, its a 88spl Johnson two stroke. I couldn't get the primer bulb to pump up. You could kind of feel the fuel come into it but it wouldn't get as solid as it should. I loaded up and came back to the house. Good thing I only live a mile from the boat ramp and not an hour away. I would have been pretty upset but no big deal. Its and old boat and will have some bugs and quirks to work out. When I got home I messed with it for a bit and when I squeezed the primer bulb, I could hear air coming from the connection where the fuel line connects to the tank. When I disconnected it from the tank I couldn't hear the air. Im going to get another quick connect and see if that will work. Im thinking that is the reason I couldn't get it to run. I believe it was sucking air.

How does a fuel system work on an older two stroke? Do they have a fuel pump of some type? I know Yamaha jet skis have a pump on the carb but it don't really have enough pumping power to pull fuel to the carb so there is a pulse line from the crank case back to the tank and that pulse pressurizes the tank to help push the fuel. Also, my plastic boat tanks have a vent valve in the cap. Do these need to be open or closed when in use?

I didn't see this addressed, but I would think that needs to be closed so the tank can build pressure for the bulb to work.

I didn't see this addressed, but I would think that needs to be closed so the tank can build pressure for the bulb to work.[/quote]

I was thinking that they should be closed but wasn't sure if they were closed, would the lack of a vent cause a vacuum and not allow fuel to flow. Kind of like a tug o war between the tank and fuel pump.

I think the vent needs to be open. I never close mine, exept over winter so no moisture can get in. If it's closed, the tank will try to collapse. If open, air can replace the expended fuel. The fuel pump can still suck fuel, as the line is submerged. Once the tank runs low on fuel, and the line is no longer submerged in gas, then the engine will quit running (out of gas).

The vent needs to be open, If it isnt it will suck a tank flat.

Open vents for use. Ask how I know...

I replaced my quick connect on the tank end and also replaced the male fitting on one tank and it fixed it. Don't know which one was actually caused the problem but it works now.

steveiam wrote:

Darin wrote:I took my toon down to the lake today for a shakedown run. Unloaded and started it but it kept dying and then I couldn't get it started. Oh yeah, its a 88spl Johnson two stroke. I couldn't get the primer bulb to pump up. You could kind of feel the fuel come into it but it wouldn't get as solid as it should. I loaded up and came back to the house. Good thing I only live a mile from the boat ramp and not an hour away. I would have been pretty upset but no big deal. Its and old boat and will have some bugs and quirks to work out. When I got home I messed with it for a bit and when I squeezed the primer bulb, I could hear air coming from the connection where the fuel line connects to the tank. When I disconnected it from the tank I couldn't hear the air. Im going to get another quick connect and see if that will work. Im thinking that is the reason I couldn't get it to run. I believe it was sucking air.

How does a fuel system work on an older two stroke? Do they have a fuel pump of some type? I know Yamaha jet skis have a pump on the carb but it don't really have enough pumping power to pull fuel to the carb so there is a pulse line from the crank case back to the tank and that pulse pressurizes the tank to help push the fuel. Also, my plastic boat tanks have a vent valve in the cap. Do these need to be open or closed when in use?

I didn't see this addressed, but I would think that needs to be closed so the tank can build pressure for the bulb to work.

Glad you were able to fix it Darin.

I made a statement not knowing what I was saying, sorry.
I really try to not do that.
Thanks for the corrections guys, I now know more than I did before.

Dammit, now belercous will see me learn something and think I'm becoming a liberal.

More than likely its the female fitting those have O rings to seal it off and those harden.

I have been reading forums on other sites and the ethanol is really playing havoc on marine fuel lines and components. Even lines built in the last few years and are that new can still have problems. Don't go to the auto parts store. You need to get it at a marine store and its has epa compliant stamp in the hose. I have seen pictures of the insides of the lines and they are literally falling apart. If your engine allows it install a 10 micron fuel filter.

Fuel tanks do need to be vented. Anyone that has run a 6 gal tank knows this. If you didnt open the vent you would be running down the lake and the motor would die. When you went to pump the bulb it was collapsed, the collapsed bulb reminded you to open the vent.

justfishing wrote:I have been reading forums on other sites and the ethanol is really playing havoc on marine fuel lines and components.

Yep, my 2006 Party Cruiser's fuel lines had "Alcohol Resistant" written all over them and this still happened in 2007. It took a year to dissolve the liner, block up the barb and destroy the fuel pump.

BOAT US paid my claim and replaced the pump, carb, lines and cleaning the fuel tank.

Mercruiser blamed Tracker, Tracker blamed Good year, West Marine had all black fuel line with no liner and I hadn't had any issues after that.

Oh and the corrosion in the carb fuel bowl ? This was WITH a water separator installed, 1 year old boat.