Large Primer Bulb - Marine Type - 1/4

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Part# 05-03690
MFR Model# 034790-10LP


Install between fuel tank and engine. A few squeezes prime your engine for easy starting. For use with 1/4" ID hose. Large (7in x 2in)


Thanks for the friendly and excellent service. The order came in short time. The primer bulb excellent replacement for the old one removed becasse of age.

Benjamin M Verified Purchase


October 12, 2021

Quick shipping, seems to be high quality item. Have not installed yet to test function.

Calvin F
November 9, 2017

The price is low which directly reflects the design and construction quality of this bulb primer. I have not disassembled it to verify but I believe the check valves are simply a plastic or rubber flapper, and are not a high quality ball-in-a-cage design. I have four problems with the unit that I received. Problem #1: The check valve at the inlet side does not block back flow. So, the fuel goes out both ends when the bulb is squeezed. Problem #2: After I purged my fuel line of air, I warmed up my engine and then went to full throttle. I observed a continuous stream of bubbles in the fuel line coming out of the primer but there were no air bubbles on the inlet side. I suspected poor clamping at the ends of the bulb was allowing air to be sucked in. So, I added two loops of safety wire clamps around each end of the bulb, and that stopped the air leak. Problem #3: This primer has significant resistance to forward flow of fuel. So, I recommend doing as I did, which was to plumb in a fuel bypass line with a check valve around the bulb primer. Problem #4: The fittings on the ends are much larger diameter than the 1/4 ID fuel line tube. Even after heating the tubes, it was very difficult to get the tubes onto the fittings.

Marvin S
October 22, 2017

It is no better than the Wal Mart brand. If there is a check valve in it, the valve does not work. The fuel line would not pump up and get tight.

August 23, 2022

Lasted about 8 months and the rubber bulb dissolved.

Jeff D
April 4, 2017

Bought this last year. Not more than 8 months old. Plane stored inside, bulb separated at both ends rubber rotted out. Would not recommend.

Jeff D
April 2, 2017


Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: What does ID stand for?

ID stands for inside diameter.

Q: Does the 7 x 2 bulb have check valves?

Yes, it has internal check valves.

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