LB1914 decomp cable

dbotos · Feb 23, 2016

Lever and bracket are there on the rear of the engine, just no cable assembly running to the dash:

1) How useful is decomp? Should I bother pursuing the cable?

2) Any idea of part number / availability of the cable assembly? I looked through the entire engine and chassis sections of the parts diagrams and didn't see it.

dbotos · Feb 23, 2016

Okay, just found it. In electrical for some reason (Electrical --> Electricity System 1 Group). 35240-34701 WIRE, DECOMPRESS ~$11. Any feedback on the usefulness of decompression on the 1914's engine or similar still appreciated.

ritcheyvs · Feb 23, 2016

This decompression lever holds some of the valves open so it's easier to spin the engine to start it. With a functioning electrical starter, decomp is totally unnecessary and may cause additional wear. Small sailboat engines (like under 20 hp) frequently have a decomp lever for manual starting, if you have a dead battery, for example. The technique is to spin the engine as fast as possible with a hand crank (decompression open) and then snap the decomp closed; hopefully spinning momentum is enough to carry through the next compression stroke and the engine will "catch." Personally, I never succeeded in starting a cold engine this way without an extra pair of hands. With a tractor on land, you should always have better options than hand cranking (like a charger or jumpers). A cruising sailboat in a remote anchorage with dead batteries may have no other options. I assume that engine was sold for other applications where that lever made more sense.

dbotos · Feb 23, 2016

So would the engine be injecting fuel during decomp'ed cranking? If so, what happens to that fuel? Blown out the exhaust? Burnt when engine finally starts? Condenses on cylinder walls?

ritcheyvs · Feb 24, 2016

dbotos said:
So would the engine be injecting fuel during decomp'ed cranking? If so, what happens to that fuel? Blown out the exhaust? Burnt when engine finally starts? Condenses on cylinder walls?

Injecting, yes. The IP and injectors work the same regardless of the decpomp lever position. I could hear the injectors fire when when I hand-cranked my old boat. Don't know what happens to to the fuel, exactly, but I suspect most of it exits through a manifold. You won't hand crank many revs, so there isn't much fuel involved.

dbotos · Feb 24, 2016

I guess I'll forgo the decomp cable for now. Could always rig up something temporary with string if I really needed it.

Cataclysm · Feb 24, 2016

Id get the cable and set it up. Might come in handy. I cant see it hurting the engine.

ritcheyvs · Feb 24, 2016

I'd leave it as is. Why spend money on and clutter things up with something you'll never use? This is a left-over from some other application for that motor. Even when I used a decomp lever, I never had a cable, I just flipped it with my hand.