Primer ball question

fish brain

Crew Member
I was out fishing the other day and after about two hours of trolling, my kicker just stalled. I gave the the ball a pump, it was a tad soft, and the motor fired right back up. Ten or fifteen minutes later it quit again. Fired the motor back up and waited near it until it tried to die again. I heard it sputter, grabbed the ball and gave it a pump and the motor came back to life, so I suspect the primer ball. Usually when I put the boat away, I disconnect the line to drain the bowl and the motor sputters and slowly dies. This was fairly abrupt almost like I turned the switch off not a slow starving of fuel like I might expect from starving the engine of fuel.
So before I start just changing out components until I solve the problem, my question is; am I on the right track looking at the primer bulb first, or should I be looking at something else first. The motor is a 2005 Yamaha T8, I replaced the primer ball about two years ago.
 
are you using chevron 94 or equivalent ethanol free fuel ? usually its the gas lines plugged up due to ethanol.
 
are you using chevron 94 or equivalent ethanol free fuel ? usually its the gas lines plugged up due to ethanol.
I try for ethanol free gas. I regularly fill up with Coop marked gas, or what ever gas the marina supplies if I am staying a a marina. My last fill up was in Tofino at the Tofino Resort and Marina. I always add a can of Seafoam or equivalent when I fuel up.
 
I've had a similar issue and it was the hose connection a little worn and would suck in air. Replaced the connection and no problems.
Good to know, thank you. So the motor would run well and then just quit?
 
Either bad o ring on the hose connector to the motor or it could be vapour lock at the fuel pump. Not sure if your year 8hp fuel pump has the water heat exchanger that they put on most models in moe recent years to prevent this problem. If the engine consistently runs for a couple hours from an initial cold start before the problem appears and then dies every 10-15 minutes after that...I lean to that being the problem. Once the engine temp gets up and the air under the cowling heats up...fuel pump vapour lock can happen. I had the same issue with my big block 9.9's and had to make my own heat exchanger to fix it. I now have a fuel pump from a newer 15hp on the motor which has a factory heat exchanger on it. I was doing the same thing initially...rushing to the primer bulb and squeezing it to catch the motor before it stalled out. PITA at the time.
 
You might try looking at the connector on the fuel tank and at the engine. There is a little "O" ring in there that the ethanol? seems to affect, causing it to swell and pop out of its seat, pushing the little check ball out of the way and reinserting the "O" ring works for a while, but in the end you will likely find that you will need to replace the fitting to cure the problem. I have found that using genuine Yamaha parts have fixed this if indeed that is your problem
 
Check the ends of the fuel lines for cracks/deteriorating rubber could remove primer bulb from equation in driveway run it see how it acts, if it fixes problem then the primer bulbs the issue
Can also pull the fuel line and stuff it in a Jerry can and run it to see if your issue lies somewhere in the boata fuel tank
 
Either bad o ring on the hose connector to the motor or it could be vapour lock at the fuel pump. Not sure if your year 8hp fuel pump has the water heat exchanger that they put on most models in moe recent years to prevent this problem. If the engine consistently runs for a couple hours from an initial cold start before the problem appears and then dies every 10-15 minutes after that...I lean to that being the problem. Once the engine temp gets up and the air under the cowling heats up...fuel pump vapour lock can happen. I had the same issue with my big block 9.9's and had to make my own heat exchanger to fix it. I now have a fuel pump from a newer 15hp on the motor which has a factory heat exchanger on it. I was doing the same thing initially...rushing to the primer bulb and squeezing it to catch the motor before it stalled out. PITA at the time.
Would the vapour lock just start out of the blue? I have trolled on this kicker for years with no stalling issues like this.
 
How's the fuel tank vent? Maybe partially plugged?
I have one tank that supplies the main and kicker. I trolled on the main for a couple of hours after I got pissed off at the kicker for stalling and then made the run in from the fishing grounds about three miles with no issue, I never say never to anything, but I'm putting a bad vent at the bottom of the list. I'm going to start with the connector at the motor and the primer bulb.
 
In my experience the vapour lock has occurred right out of the box with the firsts running of a brand new motor. However if something else has changed like a partially stuck t-stat that has the motor running a bit hotter it could start doing it all of a sudden. Less likely but not impossible.
 
sometimes a dirty carb can cause this as well...I have a 2008 yamaha 9.9 that ran like crap when I first got it a couple years back.. changed the fuel hose back to the filter, new connector/primer bulb. and then pulled the carb, disassembled and put in a carb cleaner bath overnight...blew it out with air and put it back on..it ran excellent after.

might be worth a try. (after you check all the easy things..sometimes its the smallest easiest thing that can cause you headaches)

also if the motor has an electric choke make sure it isn't shorted in the switch or in the wire run/connectors and causing the choke to close intermittently...that could cause similar symptoms.

also the previous owner opted to use tie wraps instead of hose clamps...pretty lame and susceptible to leakage.

as for trouble shooting you could wait until the motor stalls again..imidiatley pull the bowl off the carb and see if it is dry? or if you have an inline filter see if its dry . then you know that its a fuel delivery problem..most likely a bulb/vapour lock or hose/connector issue.
 
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Does you kicker fuel line T off from your main engine fuel line ? My last boat was set up like this and when running the kicker it would draw the fuel from the main engine and not front the tank. After running a few minutes it would stall. I figured out what the issue was when I would go to start that main it would take quite a bit of spinning to get it to fire compared to the other main. I changed out both primer balls the one to that main and put a complete new hose, fittings and bulb of course to the kicker, it solved the problem. The bulb to the kicker was good but it was the bulb to the main that was allowing the fuel to be drawn backwards rather than out of the tank.
Just something to look at if this is your set up.
 
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Does you kicker fuel line T off from your main engine fuel line ? My last boat was set up like this and when running the kicker it would draw the fuel from the main engine and not front the tank. After running a few minutes it would stall. I figured out what the issue was when I would go to start that main it would take quite a bit of spinning to get it to fire compared to the other main. I changed out both primer balls the one to that main and put a complete new hose, fittings and bulb of course to the kicker, it solved the problem. The bulb to the kicker was good but it was the bulb to the main that was allowing the fuel to be drawn backwards rather than out of the tank.
Just something to look at if this is your set up.
They do share the same fuel supply and come directly off the Racor Filter. I have changed the connector at the motor . I plan to go out tomorrow to test it, I hope that was the problem. If it was the problem as you describe, would; A: the engine not starve for fuel B: the primer bulb be collapsed? my bulb was about half a squeeze from hard (that's what she said)
 
I went through something similar on my 50hp efi merc last year. Had to pump the bulb continuously to get home. The fuel pump needed replacing.
 
They do share the same fuel supply and come directly off the Racor Filter. I have changed the connector at the motor . I plan to go out tomorrow to test it, I hope that was the problem. If it was the problem as you describe, would; A: the engine not starve for fuel B: the primer bulb be collapsed? my bulb was about half a squeeze from hard (that's what she said)

No those little fuel pumps don’t have enough power to collapse that bulb, all it does is slowly draw the fuel out of the main. The only way to tell if this is happening is noticing if it takes a little longer than usual for the main to fire up as it’s starved for fuel. Once it’s fired it will run as normal. I guess another question is, where is the primer bulb for your kicker in relation to the bulb for the main, or is there just one. On my boat there were two separate bulbs and the kicker bulb was before the bulb to the main.

Not sure if this is your issue but just thought it would bring it up as it’s so I experienced.
 
No those little fuel pumps don’t have enough power to collapse that bulb, all it does is slowly draw the fuel out of the main. The only way to tell if this is happening is noticing if it takes a little longer than usual for the main to fire up as it’s starved for fuel. Once it’s fired it will run as normal. I guess another question is, where is the primer bulb for your kicker in relation to the bulb for the main, or is there just one. On my boat there were two separate bulbs and the kicker bulb was before the bulb to the main.

Not sure if this is your issue but just thought it would bring it up as it’s so I experienced.
Hmmm I will throw this into the mix if my current fix doesn't work. My fuel lines are separate and have their own connection directly to the Racor filter, so I don't think one should starve the other, but anything is possible
 
Hmmm I will throw this into the mix if my current fix doesn't work. My fuel lines are separate and have their own connection directly to the Racor filter, so I don't think one should starve the other, but anything is possible

I got you, I agree if both run directly to the Racor housing then you are correct I can’t see this being your issue.
 
How's the fuel tank vent? Maybe partially plugged?
My brother in law had his boat in to three different mechanics because it kept stalling as soon as he cracked the throttle open from idle. Spent a bunch of money on them fault finding to no avail. He had looked at the fuel tank vent and ensured it was open so he had ruled that out. Found out after the vent was open but plugged. Pays to look carefully.
I doubt this problem is a vent, more likely like guys are saying an air leak or perhaps fuel pump?
 
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