Force 120 problem

[IBWET]

Has anyone had an experience with this old nail of an engine? On someone else boat today,it cut out, it didn't fart and bang so we think not fuel,one minute it was working the next it was turning over but absolutely no spark.

We held a plug next to the head no spark....

One thing that was unusual,it turned over at a quicker pace than normal.

Any idea's (mines the CPU) hope it's not, as the money is tight.

[al40]

Could be a dodgy connection on the kill switch or other wiring related issue. Normally the stop / kill switches ground a wire to kill the spark (via ECU or otherwsie) so could be something as simple as a faulty switch or the a wire has fallen off. You could try disconnecting the kill switch and see if it fires.

Where is boat located? I may be down at weekend and could have a quick look with my trusty meter if it's in the marina.



Cheers,
Al .

[IBWET]

Originally Posted by al40

Could be a dodgy connection on the kill switch or other wiring related issue. Normally the stop / kill switches ground a wire to kill the spark (via ECU or otherwsie) so could be something as simple as a faulty switch or the a wire has fallen off. You could try disconnecting the kill switch and see if it fires.

Where is boat located? I may be down at weekend and could have a quick look with my trusty meter if it's in the marina.



Cheers,
Al .

Cheers Al,




The boats at Ardlui...we tried to disconect the Kill switch but he'd lost the manual so identifying the wires wasn't easy. presently he's looking everywhere for the manual. Someone opened a beer and the manual was the excuse for stopping.


However..... if your down with said trusty instrument,you could have a look at that wee issue on that other project down in the marina we talked about ?

Iain.

[jwalker]

Originally Posted by IBWET

We held a plug next to the head no spark....

One thing that was unusual,it turned over at a quicker pace than normal.

Was that with the spark plug removed, hence no compression on that cylinder?

[Nos4r2]

Originally Posted by IBWET

we tried to disconect the Kill switch but he'd lost the manual so identifying the wires wasn't easy.

Try unplugging the controls and touching the starter solenoid trigger wire directly to the starter solenoid positive terminal from the battery to make it turn over. (the trigger wire is the SMALL one on the starter solenoid that doesn't connect to earth).

Be aware, unless it's got a stop button on the engine the only way to stop it if it starts like this is to wait til it runs out of fuel so make sure there's a water supply. DONT pull plug leads-you may bugger the ignition.

[IBWET]

Originally Posted by jwalker

Was that with the spark plug removed, hence no compression on that cylinder?

Where you been hidin ?

Jeff,
Nope the plugs were all in...,

Nos,

Fair point about the plugs, however in my defence I always ground the plug,
I've buggered a rectifier in the past, before I learned that one.


Could a/the reed/s valve have been damaged, would this reduce comp on this engine? Would it give blow back through the carb/s

I don't know it's make up, If something substantial is no longer being spun by the starter it would give a quicker spin (again don't know this engine) I'm beginning to think it could be serious?.

[Nos4r2]

Occams Razor says look at the lack of sparks first. Make sure you're not testing with a duff plug.

There's nothing substantial that can fall off/break to make a difference to starter speed unless there's no compression. Reeds won't make a difference-all of them would have to fail at once and there's more than one reed block. If it had lost compression it'd be turning over unevenly.