Little help please with Volvo issue
5.0 FL Volvo Penta
Ran great all weekend (thrus - fri).
Filled up in Whittier (added gas there thursday night and again sat).
Sunday, fill up and head back out.
Was running smooth then, while on step, stumbled and sputtered. Dropped off step so I powered down and set about changing fuel filters. Ran good then did it again. This process repeated. It would get on step and run ok for 3 to 15 minutes then stumble and fall off step again.
Fuel pump replaced this spring and carb rebuilt. Anyone have any ideas? I'm thinking water in the fuel maybe but honestly how much could be in there to cause this much isssue?
Also, it seems at idle I will hear some hissing and the idle will kick up for a few seconds then drop off. I thought to investigate this while flushing the motor and the hiss is coming from the Deceleration Valve (gulp valve). Could this be causing issues?
I don't know anything about the gulp valve, but it sounds like it's starving for fuel. Maybe the fuel pump is headed south, pinched/clogged fuel line, clogged vent, or stuck anti-siphon fitting?
Originally Posted by northwestalska
I would think the deceleration valve would not take 3 to 15 minutes to act up since it runs off vacuum and it's a valve. I think Rod In Wasilla brought up a good point with the clogged vent . The vacuum in the tank could take a while to build up then back off after you shut down.
I had water in my fuel last year to the point where there were beads of water in the venturis and on the throttle plates when it would die. I added Heet and a second water/fuel seperator. That seemed to solve the problem for me.
Another thing to look at is your coil. They tend to heat up and stop working, cool off and start working again for a short time.
Good luck and post when you figure it out.