tohatsu 4hp 2stroke reed valves

neil gleghorn

Recruit
Joined
Apr 1, 2013
Messages
1
Hi all

Hoping someone can shed light in my problem

Tohatsu 4hp 2 stroke model m4c 3f9 serial number 79130

Having removed the reed block/crankase cover while trying to resolve a non starting issue, to check the reed valves,

1. There are two reed valves , one is funtioning as it should, the other cannot open as the reed stop has it held in
the fully closed position, is this correct.

2. I have a spark but it is weak. The stator measures 53 ohms between the white and red/black wires.
3. The trigger measures 96 ohms between white/red wire and earth
4 The ignition coil measures 0.9 ohm between the spade terminal and earth
and , 58900 ohms between the spade terminal and earth.

Can anyone inform me if these radings are within tolerances.
Any help much appreciated.
Thanks Neil from the sunny Isle of Man
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Re: tohatsu 4hp 2stroke reed valves

Welcome to the forums,

1-Both reed valves should have same gap height between valve and stopper.

2-Will need a spark plug tester to test if ignition coils have a weak output.

3-If the stator is the upper flywheel ignition coil, with 53 it's way low, should be between 93-140 ohm, trigger with 96 ok (80-117 ohms.

4-Better is to test with a tester that has DVA capabilities testing electrical components outputs while cranking engine (pulling rope)

Happy Boating
 
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