RV6 0360 I seem to have an issue with fuel pump vapor locking when taxing. I have 1/2 “ cooling tubes going to both mags, alternator, and fuel pump. Would it be wise to eliminate the mags and alternator cooling and enlarge the fuel pump cooling tube? Also this issue happens even with the boost pump running.
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Fuel pump vapor lock
- Thread starter Iou
- Start date
Ralph Inkster
Well Known Member
Are your fuel lines heat protected from heat sources? Heat sleeve on all the hoses & lines, heat shields on exhaust pipes that are near the hoses, if you have a gascolator - is it directly over a tailpipe?
Dan 57
Well Known Member
Same config here… and vapor lock symptoms, but only after a short stop following a flight, and only when burning Mogas, which I do primarily.
Been fighting the same, and not isolated. Yet.
Points covered, as above, done.
Corrected, keep 1 (have 2 of em Facet) elec pump running during approach to shut-down. And before starting engine again…
Todos, check all fittings 45° bend, ditch 90°s. Finally install the the mech fuel pump shield that’s been sitting in my airfield cupboard for a couple of years
Been fighting the same, and not isolated. Yet.
Points covered, as above, done.
Corrected, keep 1 (have 2 of em Facet) elec pump running during approach to shut-down. And before starting engine again…
Todos, check all fittings 45° bend, ditch 90°s. Finally install the the mech fuel pump shield that’s been sitting in my airfield cupboard for a couple of years
Last edited:
Insulation
Fire sleeve on the fuel line is important.
Could it be that heat is transferred from the engine to the carburetor.
If so, you could install a spacer 1/4" that prevents some of the heat going to the carburetor. GRADE L PHENOLIC SHEET.
Meets Mil-I-24768/15. Tough, Economical & Good Insulation Properties.
https://www.aircraftspruce.com/catalog/mepages/phenolic.php
Good luck
Fire sleeve on the fuel line is important.
Could it be that heat is transferred from the engine to the carburetor.
If so, you could install a spacer 1/4" that prevents some of the heat going to the carburetor. GRADE L PHENOLIC SHEET.
Meets Mil-I-24768/15. Tough, Economical & Good Insulation Properties.
https://www.aircraftspruce.com/catalog/mepages/phenolic.php
Good luck
Tony Kirk
Well Known Member
Vapor Lock in a Lycoming O-360
In Ron Singh's presentation about a vapor lock incident in his RV-12iS, Rian Johnson says that he always leaves the Aux pump on in his Lycoming O-360 RV-7 (except during run-up) and he doesn't use mogas. There are a lot of good take-aways on vapor lock in this presentation. I suggest you watch the entire presentation if you run mogas in any RV.
The slide about the clogged fuel tank finger strainer that led to a fatal accident is important to everyone here - please perform a through inspection of your entire fuel system if you have a suspected fuel vapor lock issue, it may not be caused by what you initially think.
Finally, please perform through annual Condition inspections and check and clean (or replace) all filters. I know it sounds cliché but, the life you save may be your own!
In Ron Singh's presentation about a vapor lock incident in his RV-12iS, Rian Johnson says that he always leaves the Aux pump on in his Lycoming O-360 RV-7 (except during run-up) and he doesn't use mogas. There are a lot of good take-aways on vapor lock in this presentation. I suggest you watch the entire presentation if you run mogas in any RV.
The slide about the clogged fuel tank finger strainer that led to a fatal accident is important to everyone here - please perform a through inspection of your entire fuel system if you have a suspected fuel vapor lock issue, it may not be caused by what you initially think.
Finally, please perform through annual Condition inspections and check and clean (or replace) all filters. I know it sounds cliché but, the life you save may be your own!
Planecrazy232
Well Known Member
Observations
I’ve been flying my carbureted RV6A for 8 years now and have never had a vapor lock problem. A few weeks ago at our Chapter Young Eagle event, I experienced fuel pump vapor lock and a very difficult hot start, which had never happened. This same day, two other aircraft giving Young Eagle rides had the same problems, again they never had any issues. One was a RV7A and the other a Legend Cub, both carbureted. All above with 100LL. I’ve been reading more of these kind of stories lately. I wonder if a fuel formulation has changed?
I’ve been flying my carbureted RV6A for 8 years now and have never had a vapor lock problem. A few weeks ago at our Chapter Young Eagle event, I experienced fuel pump vapor lock and a very difficult hot start, which had never happened. This same day, two other aircraft giving Young Eagle rides had the same problems, again they never had any issues. One was a RV7A and the other a Legend Cub, both carbureted. All above with 100LL. I’ve been reading more of these kind of stories lately. I wonder if a fuel formulation has changed?
About fuel system inspections - does anyone know if the cheap borescopes most of us are using are "intrinsically safe" or "explosion proof?" In other words, if I put one of these borescopes in my fuel drain to inspect the fuel pickup, will it ignite the fuel vapors?
MacCool
Well Known Member
The manual for the Teslong borescope that I use states:
DO NOT use the unit in the presence of flammable substances or near electrical wiring.
WingsOnWheels
Well Known Member
Do you have a flue flow meter? Where is it located in the flow? If upstream of the fuel pump it can be a significant contributor.
