Evinrude 6hp 1981 (Belgian)

[Horsley-Anarak]

Just picked up a nice Evinrude 6hp.

Nice condition, little use and well looked after.

All good but it has lost 1/2 of its spark

I am in the process of getting my head round the electrics, there is a stator coil under the flywheel for lighting and a charge coil, also a firing sensor.

Then out side you have a power pack, and 2 further coils.

Both external coils work if fired from the working supply from the power pack.

Does this mean that the three coils are OK and the sensor is OK.

So the fault is in the power pack?

Anyone had an Evinrude/Johnson twin with only 1 spark?

H-A

[Keith.P]

I have the odd manual, mostly older stuff, but it shows three coils under the flywheel, two lighting coils, 5amp and a single primary, as the other two on the cylinder would be secondary coils, I think that sounds about right.
You could switch wires to see what works.
All the older stuff has the standard sierra type coils.

So you have your racing engine then, H-A.

[Horsley-Anarak]

So you have your racing engine then, H-A.

If I can get the spark back.

Both secondary coils work, so that means the primary coil is ok.

If the firing sensor fires one cylinder then that must be ok, it can only be the powerpack.

This is a small PCB potted in resin, so it could be just a small component failure.

But I would like confirmation before I start ripping it apart looking for a blown component.

Could it be as simple as a duff capacitor?

Where is 40 TPI when you need him ?

H-A

[Horsley-Anarak]

Here is a picture of it with the flywheel off.

I do like some of the features in this engine, and after a little research have found that it is derated.

Looks like pistons and crank are the same as the 7.5hp.

Will be looking for a restictor plate in the carb next next, and will need to check that a replacement powerpack has no rev limiting built in.

H-A

[Keith.P]

I think you will find that you will have to remove the intake manifold and file out the intake hole to match the carb outlet to get to 7.5hp, I don't think it has a plate, and maybe up the jets.

[Daryl]

Hope this is some help as i have a 1980 7.5 HP manual. Since its a CDI ignition there wont be mutch in the control module.

[Daryl]

More of manual.

[Daryl]

And some more. Most likely to be one of the SCRs or diode in the power pack.

[Horsley-Anarak]

Thanks Daryl for taking the time to do that.

I will work through that lot, and see what I get.

My engine is the same as the 7.5hp, but derated for the euro market.

Does you manual have a page about the top crank needle roller bearing Part no. 0386008, should there be any play, and if so how much is ok.

Many thanks

H-A

[Daryl]

The only info i could find on actual free play was on 1970s .0015" to .0025". Also post a circuit of a 3 cyl Evinrude CDI ign module which i dismantled to replace one faulty SCR. It was runing on only 2 cylinders & the module was very expensive. The circuit is just to give you an idea of some of the parts that may be in there. The Triac & VDR are across the HV coil to regulate the voltage at high RPM.

[Daryl]

Here is the power head part.

[Daryl]

More powerhead.

[Daryl]

Last of the powerhead. Letus know if you want the geabox & waterpump.

[Horsley-Anarak]

Perfect Darly thanks again

Managed to get the powerhead off, so many bits not like a seagull.

There is slight play in big ends, will measure later, not sure if I can get replacement bearings.

Very clean bores with original hone marks, this engine has done no work, but the bearings are showing wear.

Not sure why this would happen, or did they build them with large tolerances, am i being too critical about bearing fit?

H-A

[Daryl]

Bearing surface where needles run should be as Smooth as. If not perhaps its been run with the wrong oil mix. The 1970s specs further up should be close for clearance specs.