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The Great Train Robber

By Greg Hill

Backyard Rails GP-50

This heist didn’t require guns, nor did it require dynamite.  We're not talking spies or planes. What we're talking about here is: what is  stopping the train and killing the fun? Rest assured that no money was taken by force. The only thing removed from the scene was a good time riding the rails. The robbery started  when a Backyard Rails GP-50 belonging to my brother-in-law, Tom, would quit  running in the heat of the day. The gas engine, a Kohler M8, would run OK in cool  weather but when it got above 80 degrees F, the engine would die. This started  our little odyssey.

  We knew that we had an overheating problem. We started the normal procedure for solving this problem, which is: “ try this and if it doesn't work, try that”. But it wasn't that simple. So we asked fellow train club members and some who had the same model train if they thought it was overheating. They agreed that heat was the problem. The first possible remedy was to add another fan to remove the heat from the compartment. Nice idea, but that didn't do it. 

Backyard Rails GP-50 with cover off from above, showing original cooling fan on left and insulation covered (slightly charred) muffler in the center.

What about the EXHAUST PIPE!
We figured that better insulation on the exhaust pipe coming from the engine into the same compartment as the fuel tank should help the heat problem. The fuel tank was already insulated, so the exhaust pipe seemed to be the next logical step. The exhaust pipe was a scary sight. It wasn't the same size throughout, it wasn't straight, nor was access easy. But a job is a job so Tom and I rolled up our sleeves and dug in, or perhaps I should say inched our way into it. We used high temp insulation and did a fine job of it. The heat radiating off the pipe dropped noticeably.  Unfortunately, heat was still affecting the fuel. 

How about rerouting the GAS LINE?             The next step on the road to arresting the train robbery was to move the gas line from running through that hot compartment. Sounds great, doesn't it? My other brother-in-law, Jim (Tom's brother), and I took it upon ourselves to re-route the gasline to the outside of the engine compartment. It looked great. It was done in nice shining copper. It would cool that hot fuel before it got to the engine. But then, again, it didn't. Not a difference, no change, same old, same old. 

Let's try the CARBURETOR!
Now here is where we should have started. We were following a proper trouble-shooting technique. We logically followed the elimination of the problems that can cause a fuel system to get hot, but apparently we started from the wrong end. If we had started on the other end we could have saved time by finding the problem sooner. We thought the problem could be the carburetor.  However, before spending the money for a new carburetor, we thought that if water was pumped over the carburetor that it should alleviate the problem. 

At this time we were pretty sure that the carburetor was the culprit. The water pump worked fine, dripping cool water on the outside of the carburetor and the engine ran longer. But that was no way to run a railroad. Now who wants to run a Burlington Northern down the track that looked like it had sprung a leak? Worse yet, the engineer looked like he'd sprung a leak! 

In working around the carburetor we noticed that the mechanical fuel pump, mounted in the engine block, was there looking us right in the face…laughing, snickering, and having a blast or a gas. It was then that a light went on in our heads (some say it was a 40 watt bulb). We realized it was mounted to that hot engine. Engine gets hot, pump gets hot, and gas gets hot. VAPOR LOCK!!!!!!!!! 

The pinky is pointing to the location of the orginal fuel pump located in the engine block.

So, Tom bought an electric fuel pump (Kohler part number 41 393 45-S). We ripped out the fuel line, rerouted it to the new electric pump, then on to the carburetor and as they say, the rest is history. 

The electric pump can go anywhere.  We placed ours on the floor of the engine (see brass object under arrow).

As of the writing of this article we've been having fun riding the rails on Tom’s magic flying carpet made of steel. How about that, the BACKYARD RAILS GP-50 went from rags to flying carpet in one article. Please enjoy the knowledge provided at our expense, and have fun on your magic carpet made of steel. 

 Happy rails to you! 

the end

About the author

Greg Hill is a member of Illinois Live Steamers 

© SEPTEMBER 10, 2001 All rights reserved. This material may not be published, broadcast, rewritten, or redistributed. 

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