Restriction Caused by Primer Bulbs on Outboards
 

We found rubber pieces in the engine mounted fuel filter on a 300 x. The filter was cut open to find those pieces. The plumbing was inspected back to the primer bulb. The bulb felt spongy, cut open and missing pieces matched those seen in the filter.

The service manual suggests using an electric solenoid shutoff ILO an anti-siphon valve. However, there remains the question of initial priming. Logically, a primer bulb is potential for some amount of restriction, in it's best day.

Therefore, we are leaning towards installing an electric solenoid valve to hold the prime plus a primer bulb and ball valve in parallel with the solenoid line. The bulb would only serve to prime the fuel system, then the ball valve would be closed. The electric solenoid valve would then be expected to hold the prime. Thus, eliminating risk of restriction from a failing primer bulb.

Comments ?

I have not had that problem with my 2007 308 Skater T300XS(120 hours); however, the 300X does draw more fuel that I do.

I am courious, what vintage (age) were the primer bulbs, and has the boat seen ethanol fules?

CcanDo;3151020]We found rubber pieces in the engine mounted fuel filter on a 300 x. The filter was cut open to find those pieces. The plumbing was inspected back to the primer bulb. The bulb felt spongy, cut open and missing pieces matched those seen in the filter.

The service manual suggests using an electric solenoid shutoff ILO an anti-siphon valve. However, there remains the question of initial priming. Logically, a primer bulb is potential for some amount of restriction, in it's best day.

Therefore, we are leaning towards installing an electric solenoid valve to hold the prime plus a primer bulb and ball valve in parallel with the solenoid line. The bulb would only serve to prime the fuel system, then the ball valve would be closed. The electric solenoid valve would then be expected to hold the prime. Thus, eliminating risk of restriction from a failing primer bulb.


I had to change a primer bulb on one of my 300X's on my 28 this weekend. Would not keep prime. I just had my tanks redone by Skater. Prior to that I had a lot of fuel starvation issues with the deteriorating tanks due to ethanol.

The primer bulb which failed was the original the other which is good was replaced 10 months ago and showed signs of internal degradation when replaced.

On my old 24 and 28 I had holly fuel pumps and slosh tanks for the motor to draw from. I was surprised to see the new 28 with 300 X's rigged with primer bulbs.

I have a set of Holley fuel pumps and switches for the boat but have yet to install. Is any one using pumps?

Comments ?[/QUOTE]

The engines are 2005 w/less than 35 hrs.....new bulbs and fuel lines were installed from fuel tank to engine in 2006 when the engines were taken out of the box....no known ethanal....boat is stored in a heated/cooled warehouse.

We also checked the engine driven fuel pump and found the diaphrams to look stretched. The diaphrams are inexpensive and easy to change. However, the initial purpose of looking at the fuel pump was to look for anything unusual, after seeing the other things.... After the summation of findings it would seem there is safer way to plumb the system, sanitarily and inexpensively.

Thanks for your contribution Skate...What do you think is the best answer?

Sounds like ethanol poisoning to me. I had local gas stations advertising ethanol free fuel then next thing I know my tanks go to crap. Took half the summer to figure out the problems. Moral of story test your fuel. We had to replace the entire fuel system and plumbing.

What about the Holley fuel pumps? My 28 runs great with the primer bulbs but it seems like they would need the supply from the pumps.

Primer bulbs have been around a long time....To eliminate or plumb around them may be trying to reinvent the wheel....However, we and you have found a problem with them that can be easily managed....Potentially there is/can be restriction when the fuel must go through the bulb vs. through a straight hose...One method is to use a dual port manifold on the "out" of a remote filter head...one line runs to an electric shut off solenoid and continues to the engine...The other line runs to the bulb, to a ball valve, to a "T" that's in the line running from the solenoid to engine...Fuel doesn't pass through the bulb except for priming.

Holley and Aeromotive are not known for suction ability. Weldon and probably others are....Beyond that, we concur with the 2.5 concept, though not sure it's necessary.

i didnt have them on my 1993 300 x eliminated them you dont want the restriction get rid of the factory plastic union also another restrition go from tank to pump with one line no problems dont need the bulb or check valve

I dont believe there is a need for a primer bulb on an EFI???

Thanks ! We'll try it.

Jim thanks for the insight and info