1976 40hp tune up?

[dto60]

I bought this at a very good price, previous owner said it needed a tune up. Ordered the clymer manual ... I still don't have any idea on how to make it work. Before I fork out the money for an expert to fix it I thought I'd ask for help.

Model: 40654A
Compression: 105-110 on both cylinders
Coils: One tested fine with a resistance test the other failed
Spark: no spark on either cylinder
Plugs: both produce spark on another motor

I can't find the kill switch.
I have a white wire near the front of the motor not connected?
There are two switches that have two male wire prongs but only one wire hooked up (see IMG_0557). One I believe is the neutral switch the other I'm not sure.

Here are some pics:

Any advice would be appreciated.
Dale

 

[Bluesmobile]

Re: 1976 40hp tune up?

ok. Make sure that its in neutral with the throttle pulled all the way back. There is a safety switch that will prevent it from starting.

When you say "kill switch" i assume that you mean the switch in the 4th pic with the orange wire going from the vaccum switch. (follow orange wire up)

If memory serves me correct: the white wire should go to the starter solenoid.

Which image is 0557?

try spark after checking throttle and neutral. if still no spark, look at coils.

my seloc manual helped me alot after I got my motor and it looks like it should cover your motor too.

 

[F_R]

Re: 1976 40hp tune up?

Unlike most electrical questions posted here, your motor's wiring seems to be pretty much intact. Don't be messing with it without knowing what you are doing. By that, I mean after diagnosing a trouble spot by doing an orderly troubleshooting.

The kill switch is the key switch, up front. I don't think that motor has a lanyard (driver overboard) switch, does it?

Those two switches are supposed to have only one wire each. One of the switches prevents starting the motor in gear. The other one (under the flywheel) is the ground circuit for the vacuum cut-out switch. It allows the vacuum cut-out switch to function only at slow throttle settings. Before you ask, the vacuum cut-out switch prevents runaway if the motor is revved up without a load (Like in neutral or a lost prop). You will understand what "runaway" is if it ever happens to you. It is uncontrollable racing of the motor gone berserk.

I can't see for sure what unconnected white wire you are talking about, but it looks like some cretin has installed a car solenoid. (Cretins do it all the time.) The white wire normally goes to the (correct) solenoid. The way it is will work, but you won't have the start-in-neutral-only safety feature.

Check your breaker points, or replace them. Assuming your key is turned on, the points are the most common cause of no spark. They must have zero resistance when closed and be gapped to .020" at full open. That is zero ohms, as in 0, as in none.

When you get done doing that it is extremely important that you tighten the flywheel nut to 100-105 ft lbs with a torque wrench. Failure to do so will destroy the flywheel and crankshaft.