40hp.johnson

[RON SINCLAIR]

have a 93 40 hp. johnson. carbs rebuilt, timing set, done a linc &sync. took it out on water to set idle, 750 rpms, runs great, but when turning sharp in either direction, it stalls out, whatup with this.
thanks for any help. ron

 

[tashasdaddy]

Re: 40hp.johnson

turn motor sharp on trailer, and check spark. could be tension on a wire causing a short to ground.

 

[Ironguts]

Re: 40hp.johnson

Turning sharp puts extra load on the engine, more so then going straight. If engine stalls under load I would suspect a fuel delivery/carb problem. Did you rebuild with carb kit? You may want to check your fuel pressure as well... maybe something up with your fuel pump.

 

[tashasdaddy]

Re: 40hp.johnson

do you have an emergency kill lanyard?

 

[DGartzos]

Re: 40hp.johnson

Here is how i set up my idle (tested on big twin motors only).

Provided that carbs are clean, link and sync and WOT timing set.

1) screw right in the idle lean-rich needle valve screws on both carbs (not tight just until it touches in) and unscrew five times 1/2 a turn out each one.

2) start and warm up engine (you may need a little throttle).

3) set engine to idle at 1100 to 1200 rpm adjusting the idle spark advance stop screw. Clockwise will increase idle (advances), anticlockwise will decrease idle (retards), if that has been set correctly at timing procedure, it should not exceed a +/- 3 full turns. Make sure that the black shoe at end of this screw sits tight on stopper and if necessary readjust throttle control cable so as it pulls linkage leaver right back tight on stopper.

4) switch off engine, disconnect top spark plug and ground lead.

5) start engine on bottom cylinder only and screw in bottom carb's lean-rich needle valve 1/8 of a turn at a time, waiting for 5 sec in between each turn, until engine stalls. When it stalls unscrew 1/8 of a turn.

6) do 4) and 5) for other cylinder

7) connect both spark plugs start engine and adjust idle spark advance stop screw until 1000rpm.

8) get boat in water, warm up engine, put in reverse and adjust idle spark advance stop screw until 750rpm. Make sure that the black shoe at end of this screw sits tight on stopper and if necessary readjust throttle control cable so as it pulls linkage leaver right back tight on stopper.

9) check that butterflies engage and open at full throttle as they should and readjust if necessary.

 

[RON SINCLAIR]

Re: 40hp.johnson

the kill switch has been disabled, was done by previous owner.
i have been having problems with gas tanks, am on third one, moeller 6 gallon, they seem to expand way out of propation. these are new tanks, but the pickup hos seems to short, called moeller, they said this was normal,
have never seen this happen before.also have installed new plug wires.

 

[tashasdaddy]

Re: 40hp.johnson

leave the vent open on the tanks, when storing. does it bog down and die, or does it just shut off, like you turned the key?

 

[RON SINCLAIR]

Re: 40hp.johnson

bogs down and dies,

 

[DGartzos]

Re: 40hp.johnson

To rule out electrical cause, put boat in water, start up and test at sharp turned motor. If it is electrical it will not bog and die, it will just die, even with some throttle up. If it dies, start up and disconnect big red connector and test again, to try and locate shorting before or after connector.

If it is not electrical, which is probably the case as it bogs and then dies (too rich mixture at idle) follow my method above thread #5. It works fine on my 1994 40HP evinrude.