Does this sound like a distributor problem?

[Tao of Funk]

I have a 1969 55hp Evinrude outboard. I have really (really) replaced, cleaned, repaired, lubed, and checked everything that is externally mounted to the engine. When I take the boat out it starts right up, idles out perfectly, and "jumps" out of the water. After about 30 seconds to a minute it starts to miss on one cylinder (or more) and slow down. After that it will run at idle but will not get back up to full speed. If I let it cool down completely it'll act the same way again.

After writing that last paragraph I realize I need to hook a timing light up to the plug wires and go out to see if the problem is confined to one cylinder. I guess that may not work if there is still current flowing though the wire but it's really weak. I wonder how low the current has to be before it'll stop triggering an induction timing light?

Anyway, I know distributors go out on cars with some regularity. That's the one part of my system I can definitively say I haven't changed to see if the problem lies there.

Have you had a distributor go out on your motor? How did it react?

GB

 

[tashasdaddy]

Re: Does this sound like a distributor problem?

been along time since i had one of those, but componets in the distributor can go bad. heat up and fail, which sounds like your problem. sounds like a coil going bad on a newer motor.

 

[F_R]

Re: Does this sound like a distributor problem?

The distributors on those motors sucked. Even new, much spark power was lost somewhere in the distributor.

But that may or may not be your problem. Have you trashed the surface gap plugs and put in L77JC4 or QL77JC4 plugs? You should.

Secondly, does "everything external" include checking the breaker point gap? (.009-.010") Has the anti-reverse spring been serviced in the last 20 years? If not, they wear and the resulting metal dust contaminates the distributor cap, causing misfiring.

 

[Tao of Funk]

Re: Does this sound like a distributor problem?

Thanks guys. Yes it does include point inspection, exact gapping checked on all three lobes, and meticulously cleaning the entire shabang. I have QL77JC4's (per advice from this forum).

The amplifier and coil are "good" per checking spark with a spark gap tester and using a multimeter. I hate to think of buying a new distributor. There are very few out there and the people who have them know that...

Has anyone ever made their own distributor? I know it sounds like a big hassle and pretty involved but I could possibly modify the old one to include better connections from the strips to the spark plug terminal (I'm a bit desperate, summer will be over before I know it).

GB

 

[Dhadley]

Re: Does this sound like a distributor problem?

How's the rotor?

 

[Tao of Funk]

Re: Does this sound like a distributor problem?



Good question. I don't know how to diagnose the rotor. It's in relatively good shape. It hasn't crashed and it isn't cracked. I ensured the tip is clean and it shows no sign of carbon buildup.

How does the rotor transfer the current from the coil to the spark plug wires? If the rotor transfers the current across the gap between it's tip and the distributor cap contact strips then it must use the crank shaft as a contact (since that's the only thing it touches). In which case there is no metal to metal contact on the rotor.

I appreciate any detailed information on how a rotor transfers current to the plug wires. Thanks.

GB

 

[Tao of Funk]

Re: Does this sound like a distributor problem?

My distributor doesn't have a contact from the high voltage lead (from coil) to the rotor. The lead from the coil goes to the distributor and I can't determine how it gets to the rotor.

I would expect a lead from the coil to the rotor and then the current would jump the gap at the appropriate time to the contact strips on the distributor and to the plugs.

GB

 

[Dhadley]

Re: Does this sound like a distributor problem?

The coil lead goes into the cap and to the rotor thru the top of the rotor. As the crank turns the rotor, the spark is delivered to the plug wires from the tip of the rotor thru the distributor cap. Look in the top of the distributor cap (from underneith) and you should see a "button" that will make contact with the top center of the rotor.

 

[Tao of Funk]

Re: Does this sound like a distributor problem?

On some distributors yes, not on this particular motor.

http://12.2.215.22/pub/default.asp?SessionId=a8fe1da562e449f1a970efe78d467cb8&Lang=EN&brands=EJ

1969 55hp Evinrude

GB

 

[Dhadley]

Re: Does this sound like a distributor problem?

Then you have the round rotor. Same basic concept. The coil juice gets transfered into the center of the rotor then to the output post. Depending on where the rotor is pointed, it goes to that plug wire.

The area inside the middle of the rotor and the distributor cap itself will get carbon trails and transfer spark to the wrong cytinder. But a "misfire" could be a coil breaking down too.

What shape is the anti-reverse spring in?

 

[Tao of Funk]

Re: Does this sound like a distributor problem?

The anti-reverse spring is in good shape.

I guess I do understand the cap and rotor concept but it is strange that the coil wire is routed to the distributor cap, then over to the rotor, then back to the distributor. The answer is probably, "Yeah, it's a bad design". I have examined the rotor carefully and I can't remember any place the coils current could be passed over from the distributor. The only metal conductor on the rotor is the distribution tip.

Thanks for the input, the better I understand this thing the closer I'll be to solving the problem.

GB

 

[Tao of Funk]

Re: Does this sound like a distributor problem?

up.

 

[CharlieB]

Re: Does this sound like a distributor problem?

Two things will reduce power output,

Reduced coil voltage, which limits RPM under load

and reduced/inadequate fuel fllow. The float level drops because of a faulty fuel pump, restriction or air leak into a fuel line.

Pump up the fuel, disconnect the fuel line to the carbs and run it into a can, fire the engine and watch the flow. Good strong pulsing stream?

Careful of open fuel, don't want to burn down your boat!

 

[Tao of Funk]

Re: Does this sound like a distributor problem?

Thanks. The fuel pump has been checked and works good.

GB