PRIMER BULB COLLAPSE

[altamahajon]

Took a 14 mile trip down our local river the other day....... The motor started choking and spitting then cut off. After doing some back tracking fuel tanks, venting, lines etc. I found the primer bulb to be collapsed like a pancake. Disconnected from the main tank and depressed the small inner ball at the connector and air rushed in and filled the bulb back out... Hooked it back up to the tank primed the bulb. It got tight as it should, started the motor and headed back to the landing...  :-[ .

On the way back it collapsed again..... disconnected from main tank and hooked to my 3 gallon spare tank. Ran fine all the way back to the landing. ( Thank goodness for spares) : . I have replaced the bulb on the inline fuel line and it run fine on both tanks however not under load but all seems to be well.

My question is ......... what would cause the bulb to collapse on one tank and not the other? Both tanks are brand new from BPS, they are vented well and were open, fuel lines are fine.  

[trailboss502]

make sure your vent is not clogged up on your big tank. also check your pickup line if you have one in the tank to make sure there isnt any trash partially blocking it.

[trailboss502]

another thing make sure none of the hoses are kinked because i've had the same problem and it ended up being a kinked gas line

[altamahajon]

Thanks for reply Trailboss502. I have checked the fuel lines for kinks and they are fine.

Took the two screws that hold the fuel pump onto the block and pulled it away then squeezed the bulb..... I had fuel come out of the center hole the goes to the carbs...... from what I am understanding it should not do that and if it did that would indicate a bad fuel pump and cause the vacumn pull. Your thoughts on this before I replace the fuel pump. Talking with this person they said that I had too many connectors prior to the fuel pump....... one at the fuel tank, the bulb itself, one at the motor where it connects... from there a hose runs from the connector to the fuel pump. The hoses appear to be in good shape and when the bulb is compressed I have good fuel flow thru those....however that does not take into account any vacumn being pulled from the fuel pump...just the sqeezing of the bulb once it was replaced....

[Al Wolbach]

Those bulbs do get weaker over time and you may have fixed the problem. If it reoccurs I would check the quick disconnect on your main tank. It may not be opening the ball check valve on the hose quick disconnect. If I understand the problem correctly...........Al

[altamahajon]

That is what I am thinking.... thought about taking a hose and going into the fuel tank directly to the fuel pump. If it picks it up and runs fine then..... that should tell me it is the connectors or a restricted fuel line. Even tho I am getting fuel out at the connector prior to the motor on bulb squeeze it may not be adequate for the supply and demand. Your thoughts

[Al Wolbach]

Don't change the fuel pump. I believe it is working fine, it is supposed to pull fuel via vacuum. The problem appears to be air not replacing the space being vacated by fuel. Some type of vent problem and since it works fine on one tank then the problem must be with the other tank. I have accually heard of plastic tanks starting to collapse do to vent problems.

If I understand the problem correctly your problem must be with one tank and must be a vent problem with that tank...............Al

[Al Wolbach]

You can purchase a complete hose assembly at Wally World for less than twenty dollars and eliminate the hose entirely. It is a good idea to have a spare anyway. Just make sure you get one that is for your brand of motor so the QD's will fit... That will eliminate the hose from the equasion and give you a spare.....................I really believe the problem is the tank and probably is the QD on the tank........The only other thing it can be is the vented cap on the suspect tank. If the caps are interchangable on the two tanks change them and see what happens. I recommend you mark the caps for easy indentifing later. You can also loosen the cap on the suspect tank to allow air to enter and do the same thing......Just be careful of spilled fuel.........Al

[altamahajon]

Gentlemen, thanks for all your efforts to help me find the problem. After working all the leads from the tanks fuel line to the motor and bulb replacement..... I took the boat to the shop. The check valve in the bulb was bad after cutting it open and inspecting it but most of the time other problems will surface as well.

The mechanic took the hood off the motor checked the fuel pump and it was fine as well. Futher tracing led to the carbuerator. The line from the fuel pump to the carb was jelly soft......... taking it off and cutting into it was fuel line break down of all the alcohol that are added to our cheap refined fuels that all of us buy these days.....

Well to say the least the inside of the carburator looked like a gummed jello. :'( So the carb will be rebuilt and the fuel lines from the motor fuel line connector, fuel pump and carb will be replaced.

He did mention that seafoam on certain hoses will cause this break down as well over time........ nothing better to do than run that motor and dont let them sit up long. If they do at least crank them and run them every couple of weeks to keep them circulated well with fresh fuel.

Hope to have it back in a few days and hit the waters. At least there is a huge Boat Show in Savannah, Ga. this weekend at the International Trade and Convention CenterI can go to instead of fishing.... ;D.

May the waves be with yall. Thanks again.