Oil & Fuel PT 422 Robin Subaru Fuel Pump Necessary?

[BobRip]

I assume that you cannot use all of the gas in the tank. Perhaps my assumption is wrong. Please let us know what you find.

 

[MuncyBob]

Phil, with the fan on that side of the cage it would appear the engine heat is being blown directly at the fuel pump? This has not been an issue for you?

If the fuel is gravity fed, is it OK to have the shut off up near the gas tank?

 

[MossRoad]

I think the fan blows out, not in.

 

[Phils]

LichenLane: The fan blows in. I've noticed that the hydraulic cooler fan runs less, and I can feel air movement above the hyd cooler when I hold my had above it (maybe an unintended side benefit?). However, having the fan blow out may work as well, better, or worse but is something I haven't experimented with since all my heat problems disappeared with it this way.

Frank: the fan runs when the little toggle switch is on (you can see it in the right lower rear of the cover). I will eventually change that so it runs when the ignition is on. I was reluctant to tap into the power for the hydraulic cooler fan since I didn't know whether the wire and fuse sizes were adequate so I just ran a hot wire from the battery to a fuse to the switch to the fan. Now it's just a minor PITA to remember to switch it on. The first attempt worked so well I haven't tried anything else.

Farmall: I replaced that mechanical fuel pump years ago with electric when I was wanting to remedy the vapor-lock problem. The electric pump is located on the right side of the tub. Changing to an electric pump helped, but did not stop, the vapor-lock problem.

Phil

 

[MossRoad]

Ahh, so it blows cool air in. Interesting.

 

[MuncyBob]

Phil, I'm surprised you still have the vapor lock problem since the fan has helped your heat problem. The only time I have had the vapor lock situations have been when the pump went south from too much heat. Replace the pump and problem gone for me. I'm really hoping the gravity feed works(just as it does on my genereator and snow blower) and really can't see why it would not. I'm thinking about adding a fan on my 422 also but I would not want it to run constantly since I use the tractor in cold weather.

 

[cqaigy2]

I had a vapor lock problem as well. In order that i remember:Replaced and shortened the fuel line, put heat shield sleeve on fuel line/filter, changed out fuel filter, replaced fuel pump, disassembled/cleaned carburetor.

I found little pieces of white sealant all along the fuel path, inside the carb, filter, stuck in the fuel shut off solenoid and eventually saw some stuck in the elbow at the bottom of the fuel tank.

It seemed once i got all the crap out, i haven't had vapor lock problems. It doesn't get very warm here, probably upper 90s is warmest i've mowed. The coldest around upper teens, the fan only seemed to run while pushing snow for a couple hours.

Sure is nice living in a temperate climate especially if you like it cloudy and rainy all the time.

 

[Phils]

Phil, I'm surprised you still have the vapor lock problem since the fan has helped your heat problem. The only time I have had the vapor lock situations have been when the pump went south from too much heat. Replace the pump and problem gone for me. I'm really hoping the gravity feed works(just as it does on my genereator and snow blower) and really can't see why it would not. I'm thinking about adding a fan on my 422 also but I would not want it to run constantly since I use the tractor in cold weather.

I must've mis-communicated, Farmall.

I'd switched to an electric pump in hopes of stopping the vapor-lock. It helped.

After installing the fan, vapor-lock was gone as were other heat problems... like run-on after turning the machine off.

Good point about the cold weather... we don't have any here so I would be fine with the fan running whenever the engine is on. However, that still hasn't convinced me to re-wire the fan yet. I'd REALLY like to have that toggle switch on the "dashboard", but that would involve running wires longer and through the tunnel. So far, I just use the toggle as it is and tell myself that "someday soon" I'll change it.

I had the fan blow "in" so that the engine heat would be pushed out the muffler side. With the poor exhaust design of these PT's, I thought that drawing the air out could be sucking that hot muffler air back into the engine bay.

Phil

 

[sbalder]

I've been meaning to post a follow-up with my experiences. Our record cold-snowy winter seems to have let up and temperatures are creeping back to normal. The pumpless gravity setup with the fuel shutoff worked fine right up until the weather got above about 20F. Then I experienced a lot of surging and the occasional stall. Since I had already bought the new fuel pump I installed it and left the shutoff in the lines. The PT is back to running well now, but is still really difficult to start in cold weather. We are moving into a new house with lots of shop and garage space so I am hoping to keep this fine machine under roof all year long.

 

[SpringHollow]

It amazes me the number of people that have cars in their garage but leave their tractors outside. One must prioritize!!!! The extremely amazing thing is that my wife rarely gives me a hard time for the car being outside in the snow while the tractor is in the barn. She is definitely a keeper!!!!

Ken