Hello everyone,
I'm at a bit of a loss with our two Optimax 90 (1B802995 - 1B803159) and their primer bulbs.
If the engine sits for a while, say 10 minutes or so, I cannot pump fuel through the fuel line with the manual primer bulbs. The fuel simply doesnt get sucked upwards through the line. The odd thing is, if I disconnect the line at some stage after the bulb (Either at the engine or directly at the bulb) and pump a little bit, fuel gets sucked up. When I close it then, I can pump the bulb until its hard. I do point the arrow upwards, skywards, when I try to prime.
I have so far tried:
1. Used another fuel tank to make sure the pickup is not the problem.
2. Used another brand new pump. The old pumps work perfectly as well and have no more than 10 hours of use on them.
3. Used new fuel line to make sure there is no problem with the existing one.
4. Double checked the vent on the existing fuel tanks, they both let air in.
The problem occurred suddenly and at both engines at the same time, even though they are both completely separated from each other - own fuel tank, etc. I found that I can also temporarily fix the problem when I pump while I crank the engine. For whatever reason this allows me to again pump a bit of fuel into the primer bulb and once a bit of fuel is in there I can pump it hard.
I have recently overhauled the engines and taken literally everything apart, cleaned it and put it back together. The engines ran great for the first 10 hours or so and once I'm able to pump fuel to them they will run happy for hours, no matter the RPM.
I somehow doubt that the problem is at the engine side, but since I have changed everything else already (Fuel tank, fuel line and primer bulb) I'm a bit at a loss.
Thanks in advance for any input.