Anyone ever tried an electric fuel pump to fix vapor lock?

[packardv8]

Vapor lock on hot days seems to be a chronic problem on the 2000-series mowers with the Kohler engine. I rerouted the fuel line outside the engine shroud and run it without the side covers, but it still vapor locks on hot days.

Has anyone solved the vapor lock problem by just installing a new OEM fuel pump? How long did that prevent vapor lock?

There are small low pressure electric fuel pumps available. How much fuel pressure will the stock carb needle and seat handle?


jack vines

 

[reynoldston]

Are you sure you are having a vapor lock problem. Never ran across it in anything. I guess it can happen if a gas line ran close to a exhaust pipe. Your fuel would have to be to the temperature of boiling turning it to vapor causing a vapor lock.

 

[BWH]

Vapor lock on hot days seems to be a chronic problem on the 2000-series mowers with the Kohler engine. I rerouted the fuel line outside the engine shroud and run it without the side covers, but it still vapor locks on hot days.

Has anyone solved the vapor lock problem by just installing a new OEM fuel pump? How long did that prevent vapor lock?

There are small low pressure electric fuel pumps available. How much fuel pressure will the stock carb needle and seat handle?


jack vines

I've never had vapor locking problems on my mowers but I did have that problem on a 1979 Dodge Power Wagon 400, it would vapor lock around the mechanical fuel pump so I mounted an electric fuel pump at the rear of the truck by the fuel tank which took care of the problem. I tried to insulate and reroute the fuel lines but with the mechanical fuel pump located on the side of the engine I just could not eliminate enough heat.

I don't know how much pressure those fuel pumps for small engines run but I do know they work well, I had one mounted on a Bolens garden tractor where the tank when below 1/4 tank was lower than the carburetor. I used it for years without any problems.

 

[bertsmobile1]

In case you missed it on the other post,
Probably about a 90% chance it will be an accumulation of dust & debris in the fuel tank blocking off the fuel outlet.

 

[greynold99]

Packardv8,

I spoke several times with you last couple of years... I finally did replace the fuel pump with an OEM replacement last Summer and that, along with routing the fuel line around the 'steel-tube pass-thru the engine to the carb design' around the firewall, fixed the problem completely on my 2135 (1996) Cub.
I think I mentioned, it takes a little longer to get her started with the gas having to pass through the extra length of fuel line to the carb on the other side but other than that - no more vapor lock.

First thing I noticed after replacing the fuel pump was how much smoother the engine sounded and ran. I could see no real discernible wear on the metal fuel-lever actuator (driven off the camshaft lobe) but supposing when it got hot, the space-tolerances increased the space aggravating the apparent vapor lock issue.
New fuel pump from RepairClinic.com was around $50 - probably about the same as an electric fuel pump.

I'm posting a new topic on something I discovered with the hydrostatic transmission, that if you can provide your insight, I'd appreciate it.
Thanks,
greynold99

 

[packardv8]

In case you missed it on the other post,
Probably about a 90% chance it will be an accumulation of dust & debris in the fuel tank blocking off the fuel outlet.

I finally did replace the fuel pump with an OEM replacement last Summer and that, along with routing the fuel line around the 'steel-tube pass-thru the engine to the carb design' around the firewall, fixed the problem completely on my 2135 (1996) Cub.

Just to test out all three theories, I'm going to wait for the first hot day when it dies out from lack of fuel, blow back through the line and see if it temporarily clears the problem.

If it doesn't, then I'll try one of the small electric pumps to see if that ends the symptoms. There's the possibility even a small auto pump is too strong for the little needle and seat.

Third option will be a new OEM fuel pump.

jack vines

 

[Rivets]

Before you purchase an electric fuel pump, I must warn you that most carb float valves are not set up for that pressure. You may run into an extremely rich mixture and flooding.

 

[reynoldston]

Before you purchase an electric fuel pump, I must warn you that most carb float valves are not set up for that pressure. You may run into an extremely rich mixture and flooding.

A couple of years back I ran across this problem on a International Farm tractor I worked on for a customer. Fuel pump pressure too high. As I recall I found they sold a real low pressure electric fuel pump at the farm tractor dealer. So if you do buy a electric fuel just beware what psi it puts out. With the newer EFI systems it can become a problem.

 

[packardv8]

Could have found the problem today. Was adjusting the blade tracking and noticed fuel drip. Wiped down the fuel feed line to the filter and found a split along the seam.

It's possible the split was such it previously wouldn't leak fuel out under atmospheric pressure, but under vacuum from the fuel pump, it would suck air instead of fuel from the tank. Similar symptom to vapor lock, just different cause.

I cut 2" off the feed line and we'll see what happens on the next hot day.

jack vines