M H 50 high altitude

44 special · Jan 3, 2016

I have a M H 50 high altitude , there is a tag that says do not operate under 5000 feet. Has anyone seen this before, and what can be done to use at an altitude of 1000 feet. Thank You for any help.

miner09 · Jan 3, 2016

Change jets in carburetor.

Dieseltech · Jan 3, 2016

I'd get it on a PTO dynamometer to place it under load to reset the timing, it may need retarded some. You DON'T want it to ping when under full load, carb can then be set then also. That's a rare engine around here, take good care of it..

Steven-Id · Jan 3, 2016

I have both a 1958 mf50 and a 1958 mf 65. They are both high arch models and they both have the stickers that say high altitude on them. I understand that they have a different compression ratio and you set the timing different. I haven't changed the jets in them as I am at about 4700 feet of elevation so I haven't worried about them.

Steven

ptfarmer · Jan 4, 2016

On the 50 the high altitude engine has a 8.0:1 compression ratio, on the ones used at lower altitudes has a 6.6:1 compression ratio. Since you have less oxygen at a higher altitude they raised the compression ratio so the engine can make the same power as the lower compression engine does at sea level. The pistons (which is the main difference) for the high altitude engines are hard if not impossible to find.

M H 50 high altitude

44 special

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miner09

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Dieseltech

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Steven-Id

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ptfarmer

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