Jump to content
Touring Motor Gliders Association (TMGA)
mikeschumann

Electric Fuel Pump

Recommended Posts

mikeschumann

As part of the standard engine start checklist, I test the electric fuel pump..Not only due I listen to see if it is running, but I also wait to see the fuel pressure rise, which used to take about 20-30 seconds. 

Recently it has taken much longer for the fuel pump to prime. During the last couple of flights I gave up waiting for the fuel pressure to come up and just started the engine without the electric pump on.  The engine started normally. 

Does anyone have any ideas on why the electric pump is not priming?  Is this something I should be worried about?

Share this post


Link to post
Share on other sites
Eric Greenwell

I rarely watch the pump pressure when testing the electric fuel pump; instead, I watch the fuel flow into the filter near the pump. If the plane has be unused for several days, a lot of fuel flows for a few seconds, then it diminishes to almost zero (I think it's filling the carb bowl, then some is fed from the carbs back to the left tank). As long as the timing and fuel flows seem normal, I'm happy. I do occasionally check the fuel pressure widget on the Skyview. I'm not suggesting this better than checking the fuel pressure, but does give you different information.

So, does your pump put fuel through filter, suggestig the pump is just not producing as much pressure as before? Or is it not putting out any fuel at all, suggesting pump might not have fuel on the inlet, or that the check valve is blocked?

Share this post


Link to post
Share on other sites
mikeschumann

I'm in the cockpit when I check the fuel pump, so I have no idea what is going on in the filter.  It sounds like a priming issue, or maybe a stuck check valve (or vapor lock).  It's definitely not pumping or there would be pressure.  I can't tell if it is pumping when I turn it on after the engine is running.

Next time I land, I will leave the fuel pump on when I shut down the engine and see what happens with the fuel pressure.

Share this post


Link to post
Share on other sites
Eric Greenwell

I check the fuel flow into the filter with the top cowling off, of course, but checking the pressure from the cockpit display like you do sounds like a good additional check. I don't know why I haven't been doing it every flight, instead of sporadically. I don't recall it taking more than 10 seconds to build up pressure, but I will measure it next time I fly.

Share this post


Link to post
Share on other sites
mikeschumann

This afternoon I left the electric fuel pump on after landing and shutdown the engine. Over 30-60 seconds the fuel pressure slowly dropped to 0. Looks like I need to replace the pump. Does anyone know the part number and a source for the pump?

Share this post


Link to post
Share on other sites
mikeschumann

I replaced the pump.  The part number was on the component list that came with my motorglider.  Bought the pump on E-Bay for $85 (new).  Solved the problem, so it was definitely a defective fuel pump.  The check valve was OK.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...