Two year saga of suspected fuel-starvation issue on Cub HDS 2135, Kohler 12hp engine

[greynold99]

Ok! This past weekend I changed over the fuel line to bypass the metal fuel tube through the engine shroud and mounted it on the firewall. While I was at it, I changed the fuel pump as well. Aside from a slight bit of wear on the cam-driven pump-lever coming out the back of the old fuel pump, I couldn't see anything significantly wrong.
The only difference was that the fuel-line connections are now plastic/nylon instead of metal; and you have to use a split-ring tool to depress the internal locking retainer ring so the rubber O-ring seals on the plastic connection nipples aren't damaged when you insert them.

Other than that, pretty much a snap to install.

I ran the tractor a half-hour afterwards to check for any fuel leaks, not enough to verify that it has absolutely fixed the problem but the first thing I noticed was how fast it started up even with the additional length of fuel line. I mean there was almost no cranking before she started up. Plus it seemed like a smoother running condition - no noticeable additional power just more consistent power if that makes sense.

Soon as the rainy period is over here I'll be on it to test the heating/shut-off issue.
greynold99

 

[packardv8]

Running the fuel line around back outside the shroud didn't cure the problem, but today, I removed both side panels and mowed in 90+ heat and no vapor lock! Now, the question is would just removing the side panels have been enough?

jack vines

 

[greynold99]

packardv8,

Well I'm crossing my fingers as I write this - but since replacing the fuel pump and routing the fuel line to the firewall, bypassing the metal fuel tube through the engine shroud; I've mowed maybe 4 times and have had no problems with heat-related engine shut-off. Last time was this past Saturday when the temp was around 87 degrees F.

Though I must admit I've not reset the right side-panel cover - not wanting to tempt fate in thinking I've fixed the problem. But so far so good.

It does take a little bit more extra crank time on the starter to get the fuel through the extra bit of hose needed to route the fuel line directly to the carburetor; but once she starts, she's running.

As I mentioned, the new fuel pump seemed to even-out the fuel delivery for a smoother running engine but no significant change or increase in power as a result. So, it could very well be a combination issue as you thought earlier with the heat and worn fuel pump lever-cam.
If your Cub has any where near 500 use hours on it, might be worth replacing the fuel pump if you haven't done that already.
Later,
greynold99