1986 merc.115 tower of power staring problem

Just had new carbs rebuilt and I am having problems starting the motor. When I pump the ball it does not get hard. I can hear gas in the bulb but I was told to pump the ball until hard, the put the key in the ignition and push in to choke it. I did manange to get it going and it seems to run fine except when I pull a tube. With a tube in tow it stalls out when I hit it out of the hole. Without the tube it comes out of the tube just fine and gets up on step easily.
What do you think the problem is?
Thank you.

Re: 1986 merc.115 tower of power staring problem

Did you check the carburetor to make sure it's not leaking any fuel? Also, check your fuel lines from the fuel pump to make sure you're getting solid fuel flow.

Re: 1986 merc.115 tower of power staring problem

Remove the cowling for the motor, pump primer bulb n check for gas pouring out of one of the 3 carbs throat. When you went through the carbs did you verify the float height and verify all 3 were good still?

Re: 1986 merc.115 tower of power staring problem

Without an accelerator pump two stroke idle mixtures have to be excessively fat to provide the additional fuel needed for crisp acceleration.

The increased load of pulling a tuber is just enough increase in load to require a slightly richer idle mixture.

Open each idle mixture screw just the width of the screwdriver blade slot, test your holeshot with the tuber. You may have to repeat the adjustment once or twice.

Edit: If the motor used to pull up a tuber or skier and now it doesn't then it could be a sign that the carbs are sufficiently dirty they need to be cleaned.

Re: 1986 merc.115 tower of power staring problem

I was told the ball should get hard when you pump it? I am wondering why it does not get hard. Any other suggestions. I just paid $700.00 rebuild the carbs.
Any other ideas?
Thank you.

Re: 1986 merc.115 tower of power staring problem

Call the repair shop and verify that they did a link-and sync.

Is it time for a new fuel hose? Get the the thick one with the larger fuel-flow...I forget if it's 5/8 or what.

Re: 1986 merc.115 tower of power staring problem

Opto, I did the carbs and fuel pump on my buddies '86 115horse. If we stop to chill for a few hours, upon trying to start the motor again you have to prime the bulb. And the bulb never gets fully hard. Not sure if these are just these motors or we both have the same issue.....

Re: 1986 merc.115 tower of power staring problem

P.S. do you still have the idle stabilizer in yours? We took ours out (advice from CDI rep) as they are not entirely necessary, and it made a huge difference in hole shot.

Re: 1986 merc.115 tower of power staring problem

The floats in those old stacked 6's are very light, it does not take much pressure to overcome the float and flood the carbs.

Less than a firm handshake is all that is needed to fill the carbs.

The bulb will only remain firm when you first pump it up firm, once the motor is running and the fuel pump sucks on it it will seem like it takes a little more than a half a squeeze to get that firm again.

Did you fatten the idle mixture that slight amount and cure your holeshot issue pulling a tuber?

Merc primer bulbs are the best, they have check valves in both ends. Most all aftermarket bulbs only have one check valve and many have a bad habit of allowing fuel to drain back. Many owners refuse to use an aftermarket primer and insist on factory.