No sparking v4

[Beakster]

Got a 100. Started fine, cut out. Now no spark. Where to look?

 

[Crosbyman]

look for the mdl number on the engine....

 

[stresspoint]

where to start ??? , grounds on CDIs , grounds on coils , for that matter all grounds on the ignition system.

 

[Chris1956]

Kill switch tripped?

 

[saltchuckmatt]

Got $100?

That will probably fix it if you learn how to diagnose.

Try deductive reasoning.

 

[Beakster]

Managed to get her started.... I first tried disconnecting the black and yellow wire from the ignition switch, no change.

Then I cut the black and yellow wires off the blue power packs and she started up.

I presume somehow somewhere those wires got earthed. I'll need to crimp on bullet connectors so I can reattach them. Any ideas on where those wires are known to ground? Or should I unwrap the whole wiring loom?

Thanks

 

[Chris1956]

On my '98 Johnny OB, the boat harness was melted where it plugged into the engine harness. I am not sure where the short was, but the short caused the wires to melt at that point. I also found melted wires under the dashboard.

In general, look for places that the wires need to bend. That is usually where the trouble is.

I would trace the wires from engine thru plug into harness in the boat. If you do not find it, look where wires go into controls.

 

[saltchuckmatt]

Mine went bad near the motor where it swivels a lot.

No need to open the whole harness, just some spots and test each wire for continuity.

Another trick if the harness is already exposed is dig your thumb nail along the wire....it usually squishes in where the brake is.

 

[jimmbo]

Got a 100. Started fine, cut out. Now no spark. Where to look?

1966 - 1968?
1971, 1972?
1978 - 1980?
These are just some of the years that there was a 100hp, and all are different.

 

[oldboat1]

Corrosion is common to all. Sandpaper connections until shiny as a first step.

 

[Beakster]

It's a 1980. I think I found the problem. I was in a hurry the day I posted, hence the concise message. I ended up cutting the black and yellow wires to get the boat going so I could get home.

Once I had time to investigate properly I found that the wiring loom under the flywheel had been rubbing on the flywheel. Looks like it's rubbed through and grounded some wires.

Next step is to fix the cut black and yellow wires by crimping on bullet connectors, pull the flywheel and repair the damage.

There doesnt appear to be a clamp under the flywheel to hold the loom in place.

My 1/4" impact driver is rated for 116ft/lbs, but it is only 1/4". Will that be sufficient to torque the flywheel back down? I don't want to buy another tool just for this job.

 

[Crosbyman]

proper torque can only be met with the use of a torque wrench.

to answer your question.... on small HPs engines I pretty much use my 1/4 impect driver. no problems yet .

up to you

 

[Beakster]

proper torque can only be met with the use of a torque wrench.

to answer your question.... on small HPs engines I pretty much use my 1/4 impect driver. no problems yet .

up to you

Problem with a torque wrench is how do you stop the engine turning while torquing the flywheel?

 

[Chris1956]

Gee, there are a myriad of tools for just that purpose, but sticking a heavy screwdriver somewhere to wedge it works.

 

[Beakster]

Gee, there are a myriad of tools for just that purpose, but sticking a heavy screwdriver somewhere to wedge it works.

Tried that originally, but couldn't find anywhere on the v4 to hold it while I applied 100ftlbs of torque. Anywhere I tried, like the lifting eye, it would lever it round.

 

[jimmbo]

Problem with a torque wrench is how do you stop the engine turning while torquing the flywheel?

As mentioned, there are Tools for that, I've used a Strap Wrench, others have found places to Wedge Pieces of Wood to jam the Flywheel.

 

[racerone]

???-----Go to an automotive store.----Find or ask for a " flywheel turning tool "----Hint----you can use this tool to stop the flywheel from turning.

 

[stresspoint]

i just stab a big flat head screw driver in the teeth on the FW and wedge against the starter, get someone to hold it there whilst i torque the nut,
get it in the right spot and the screwdriver will stay in place once tension is on the nut , however it works better with a helper pushing the screwdriver in place..
that said , i have also used the impact gun on high and some common sense to lock the nut in place.

 

[Chris1956]

A lot of those Johnnyrudes need the flywheel torqued exactly to the spec, or the key will shear. I would therefore recommend you get the exact torque spec, if you don't already have it.

 

[saltchuckmatt]

Not sure why everyone is working so hard.

Strap and torque wrench.

Easy and cheap.