Lehr Outboard Bogs Down

[SKMT]

I have a 5hp Lehr propane outboard that came with my trawler. I starts right up. And runs fine thru the rpm range, but then after awhile it tends to bog down at full throttle to the point I might as well just throttle back to about 2/3rds because thats all i'm getting. Also have had issues with it getting bad enough that it would die.

Any opinions on the cause?

[MikeHoncho]

how cold is it air wise? It might be that the tank isn't producing enough propane gas due to a combination of auto refrigerating and cold atmospheric air.

[SKMT]

80 degrees. It's a 10lb fiberglass tank, but its only about 1/5th full.

[MikeHoncho]

When liquified gases vaporize they cool dramatically that hinders their ability to further vaporize. More liquid mass hinders this potential. 80f helps but at only 1/5th there is minimal mass. I don’t know how much gaseous volume the 5hp uses as compared to what I know as a volume/leak needed to autorefrigerate a tank. I’d have the tank filled and try it. More likely than not the problem will remain but at least you would know it’s not what I described. I’d also research inline filters/screens on the motor.

[AA3JY]

There is a Lehr Owner FB Group site for shared info..

[tkeithlu]

The "it would die" sounds like ice in the propane line. Just a little water in the line and the cooling from LPG vaporizing can make ice.

[SKMT]

I topped off the 10lb tank and it still bogs after about 10-15 minutes.

Posted on the Lehr FB group yesterday, bit no responses.