Hard cold start after trailering?

[FatTire]

We have an old snowcat powered by a 1985 Mercedes OM617A 5cyl diesel with 2400 hours. At 15 to 18 deg the cold engine fires right up after sitting all night after about 15 sec on the glow plugs (w/o the blockheater). But it seems repeatable that if I trailer it home and the cat sits on the trailer all night, it takes about 5 long cranks to get it started. Last night I fired it up when I got home with it on the trailer, engine was still a little warm, and it started easy. Let it sit on the trailer overnight, and it started easy at 19F this morning. This fits the pattern -- it is hard to cold start only if I trailer it and have to start it cold.

Last winter I thought maybe this problem was related to vibration on the trailer causing air to get into the fuel system, so over the summer I replaced most segments of fuel line and tightened all the clamps, with new fuel filters following a "diesel purge". Now it looks like it didn't help at all. (Diesel purge is just some solvent run through the injectors, but the Mercedes enthusiasts swear by it for this particular engine.) I "think" it starts quicker after the purge, but maybe that's like a placebo effect.

Hope I explained this problem well enough.

Thoughts?

 

[FatTire]

We have an old snowcat powered by a 1985 Mercedes OM617A 5cyl diesel with 2400 hours. At 15 to 18 deg the cold engine fires right up after sitting all night after about 15 sec on the glow plugs (w/o the blockheater). But it seems repeatable that if I trailer it home and the cat sits on the trailer all night, it takes about 5 long cranks to get it started. Last night I fired it up when I got home with it on the trailer, engine was still a little warm, and it started easy. Let it sit on the trailer overnight, and it started easy at 19F this morning. This fits the pattern -- it is hard to cold start only if I trailer it and have to start it cold.

Last winter I thought maybe this problem was related to vibration on the trailer causing air to get into the fuel system, so over the summer I replaced most segments of fuel line and tightened all the clamps, with new fuel filters following a "diesel purge". Now it looks like it didn't help at all. (Diesel purge is just some solvent run through the injectors, but the Mercedes enthusiasts swear by it for this particular engine.) I "think" it starts quicker after the purge, but maybe that's like a placebo effect.

Hope I explained this problem well enough.

Thoughts?

It should be clear that the big issue is trailering somewhere and arriving with a cold cat. It isnt that big of a deal here at home.

 

[Stimw]

Trailering would expose it to more cold from air flow especially the air intake.
I have a Branson 3510 and below 50* I need to cycle the glow plugs several times for a better start.
Haven't checked to see if all mine are working. ??

 

[FatTire]

I've tried multiple glow cycles after trailering, and all five GP's are functioning. On this machine the Glow Plug timer is based on temperature, but after the light goes out the plugs remain energized until 18 seconds has past, so I usually crank at 15 seconds. If no start i hit the GP's again before cranking again.

 

[kthompson]

Are you adding fuel to it when it is being trailered and if so is it fuel you haul from home or fuel you are buying where you are running it? If would suspect something about the fuel. Another thought is it possible there is trash being stirred up in fuel tank that is being pulled onto or into the pickup tube in the tank? I had issue with a tractor few years back that was odd and turned out to be dead wasp floating in the tank.

 

[FatTire]

Are you adding fuel to it when it is being trailered and if so is it fuel you haul from home or fuel you are buying where you are running it? If would suspect something about the fuel. Another thought is it possible there is trash being stirred up in fuel tank that is being pulled onto or into the pickup tube in the tank? I had issue with a tractor few years back that was odd and turned out to be dead wasp floating in the tank.

I fuel up out of our own tank, but the idea of stirring up the fuel in the machine's tank is interesting. Next time I have the problem I could pull a fuel line and feed it from bottle of clean fuel and see if that does anything.

 

[boomer1025]

Try covering the exhaust and air intake after you load it on the trailer for the trip