1968 40 horse won't start

[Alpendel]

Ran good when taken out of water last winter.
New fuel 50:1 this spring, would not start. Fires up momentarily when fuel sprayed in Carb venturi, but immediately dies.
Carb boiled out and new kit installed, compression 110 on both cylinders.
Fuel line pumps up.
Reed valves are clean and appear perfect.
Local shop will not work on this old of engine.
I am in need of all the help I can get.
Thanks

[Elton Smith]

Have you checked the fuel pump.Sounds like a fuel problem.Sometimes those old diaframs just stretch out.

[Alpendel]

won't start

New fuel pump didn't help.
Still need help bad.
Thanks

[jelasea]

Neutral safety switch

I had a problem with this on my 1968 33HP would not start, replaced the switch and the problem was solved.

[Alpendel]

Thought of that because it just quits when I turn the key loose.
Somebody tell me how to byp*** the switch and pull start it. (Ugh)

[jelasea]

Neutral safety switch

To test the neutral switch pull the wire on inlet side of switch and ground it to the engine. Then try and start it.

[Elton Smith]

I think on those motors, you can unplug the coils to the kill switch.There should be a connection from the coils in the wireing harness.That will open the coils to fire.If either coil wire is touching the other they will ground out. You may have to pull the plug wires to kill it.

[Alpendel]

Still won't start.

The engine will start on starting fluid or a shot of gas in the carb. Just uses it up and quits.
Wouldn't that eliminate a switch problem?
Thanks

[Elton Smith]

Yes,at least you know the coils aren't grounded.If they were it would not fire at all. ok tries to start but has no fuel.Check the primer bulb.If it feels funny something is not right.See if it will run with the choke on.May have to use spray bottle.Were headed for a bad fuel pump or something in the carb is stopped up.To check the fuel pump pull the hose on the carb off turn the motor over and see if you get a good squirt. Hold you thumb on the end of the hose to see if the fuel pump has pressure.If it does were down to the carb.If it don't we need to check the crank case.

[Alpendel]

That cranky 40 horse,

Appreciate your input greatly.
Is there a way to check the vacuum from the crankcase?
Might a pretty good shade tree mechanic overhaul it (me)?

[Elton Smith]

If the fuel pump squirts gas the crank case must be ok.The fuel pump uses the vaccum to work.Check the vaccum hoses that come out of the crank case for leaks.Test the compresson of the cylinders.The only thing left is the carb may still be stopped up.Low compression is not good.