What I learned about my fuel system

[wooslehunter]

I thought I'd share this. I had a fuel starvation problem that I eventually tracked to something I didn't expect - a clogged filter I didn't know I had. To those in the know it may be obvious.

The engine was installed professionally before I bought the boat & has been working for the last 9 years I believe. The fuel is unfiltered from the tank to the lift pump. The main filter is between the lift pump & the injection pump.

Once the fuel starvation problem happened, the bleed pump would not suck at all & I eventually tracked the problem to the lift pump. This was a pig to remove due to its location & even worse to put back. Once I dismantled it, I found a small gauze filter that was completely choked. After cleaning & reassembling the system seems fine.

So, even though the system was professionally fitted, there should have been a filter after the tank. I'd always thought this but relied on the installers knowledge, I didn't know there was a filter in the lift pump & the fact that it had been running for years without a problem.

I'll be fitting a primary filter in the line from the tank as soon as it arrives.

 

[oldharry]

Very unusual to have no primary filter before the fuel reaches the lift pump, for precisely the reasons you have described. The gauze filter is there to protect the pump itself, as larger particles would prevent the valves from closing and cause premature failure.

Very wise to install a primary filter.

 

[Stork_III]

I thought I'd share this. I had a fuel starvation problem that I eventually tracked to something I didn't expect - a clogged filter I didn't know I had. To those in the know it may be obvious.

The engine was installed professionally before I bought the boat & has been working for the last 9 years I believe. The fuel is unfiltered from the tank to the lift pump. The main filter is between the lift pump & the injection pump.

Once the fuel starvation problem happened, the bleed pump would not suck at all & I eventually tracked the problem to the lift pump. This was a pig to remove due to its location & even worse to put back. Once I dismantled it, I found a small gauze filter that was completely choked. After cleaning & reassembling the system seems fine.

So, even though the system was professionally fitted, there should have been a filter after the tank. I'd always thought this but relied on the installers knowledge, I didn't know there was a filter in the lift pump & the fact that it had been running for years without a problem.

I'll be fitting a primary filter in the line from the tank as soon as it arrives.

On VP engines the primary filter is an optional extra. VP fit the small guaze filter in the banjo onto the lift pump in case option not fitted. It should be removed if primary is fitted. In many cases it is not removed.

 

[pvb]

Another Volvo Penta tip - in many installations, the tank uses the Volvo Penta tank plate and fittings. The pick-up pipe has a fine metal gauze filter, hidden away in the murky depths of the tank. If you have fuel problems, it's worth removing the pick-up pipe and cleaning the filter.