28hp Evinrude Speeditwin Mystery - all theories welcome

[Crosbyman]

I think membership on fiberglassics is pretty cheap maybe you should join up and ask the resident experts on Crosby boats.

My Cruisette had some rot issues in the double floor and I changed some runners and resealed it up.

 

[kdiddle]

Well, I have an update. After removing engine again, checking the exhaust cover for leaks and resealing, I went back to checking ignition. While the spark on the lower cylinder seems to jump a sizable distance, one thing I hadn't tried is feeling the difference in the spark plug wires. Suffice it to say that the upper cylinder (that's running great) has a lot more 'bite' to it. Although you could feel the spark on the lower wire, it was a far cry less of a shock than the upper wire.

Which begs the question - with all new ignition parts (lower coil/condenser/points replaced twice), gap set, new metal core wires, etc....any idea what would be restricting the spark on the lower cylinder?

 

[racerone]

Wrong air gap at the " heels " of the coils.----Wrong point gap.-----Defective coil or condenser.-------Coils can be set with a locating ring.-----Points can be set using a multi meter and the timing marks.----Two timing marks on the flywheel at 180 degrees apart..---2 vertical timing marks on the magplate.

 

[kdiddle]

I suppose I could buy a 3rd set of points/coil/condensers and try that, but you mention using a voltmeter for setting points. I'm simply setting gap at .020 where flywheel key lines up with point cam lifter. Is that not an acceptable means of setting points? It seems to be working on the upper cylinder without issue...

 

[racerone]

There is an acceptable way to set points and there is a BEST way to set them.------Up to you to research.------Search for ----universal magneto -----There is lots of information for you !-----Points need to open at the CORRECT time for maximum spark to be the result.

 

[kdiddle]

For those interested, see attached

 

[Chinewalker]

Often, new points have a film on them from the manufacturing process, or even just finger oils from handling during installation. Make sure they are CLEAN! Even slightly dirty points can really suck the life out of the spark.

 

[kdiddle]

Thanks for the tip, Chinewalker. I'll make sure and hit them with some brake cleaner before I button it back up again. I've ordered an adjustable spark plug tester to see if I can get the 1/4" spark (but I'm assuming I won't). At that point, I may have no option but to swap all the ignition parts from one side to the other to see if the issue follows the components.

 

[oldboat1]

Standing in the rear of the engine, the bottom coil will be closest to you, and the points/condenser on the right go with that coil. Make sure the plug wire for that coil is routed to the bottom plug.

A little acetone or lacquer thinner on a matchbook cover makes a good tool for cleaning points.

 

[kdiddle]

I officially give up. I'm going to post somewhere (not sure if its allowed on iBoats or not) to see if I can find someone local willing to come take a looksee in exchange for some dinero. I've tried local boat mechanics, but no one seems to want to work on an engine this old.

For those that might care, the latest steps taken to track down my lower cylinder ignition gremlin:
1) Tested HV/Coil continuity - confirmed both cylinders had acceptable values (11ohms) and the values for both were nearly identical. This also verifies no break in the newly installed spark plug wire
2) Open breaker test - both breakers had same value of @1ohm when open
3) Closed breaker test - both cylinders had same value of @.1ohm when closed
4) Capacitor test - both capacitors had similar capacitance/ohm values
5) Coil swap - I went ahead and swapped the coils since the top one was known to work.

The outcome to all of this is no change. After swapping the coils around (what a PITA) and testing with my spark plug tester, the upper cylinder still has the fire of Thor and the lower cylinder has barely enough to bite you. I'm literally at a loss. I sat and stared at my magneto plate from every conceivable angle looking for a bare wire, short, anything that could be killing my lower spark - but I got nothing.

 

[kdiddle]

So if you or anyone you know is a capable Evinrude guru in the greater Atlanta area, I'm willing to drag it wherever necessary and am willing to pay well to get this $%^# thing figured out.

 

[racerone]

You have to tell some shops that you are willing to pay and not complain at the amount.

 

[F_R]

A quick glance at the Antique Outboard Club's membership directory shows 40 members in Georgia, three of them in Atlanta. Sorry, I'm not at liberty to reveal their names & stats to non-members. I suggest you post your plea on the club's Ask-A-Member forum at www.aomci.org and see if anybody responds. Hey, consider joining the club while you are at it.

 

[Grub54891]

On the port side of the motor, there is a diaphragm type device, not a fuel pump. It has a wire going to it, not sure but it may have something to do with ignition. Rev limiter?? Follow them wires to see where they go. If it's to do with cutting out one cylinder, I'd like to know also. I don't have your issue, and it looks like you have tried most any other test. Let me know how it goes.

 

[Grub54891]

One more thought, Did you replace the crankshaft seals? If they are bad, it will run lean on that cylinder, and not give you the power you are looking for.

 

[kdiddle]

Cross-posting from the restoration page, since this forum is where all the Evinrude gurus reside...

Just wanted to circle back and provide an update on my issue. I ended up taking it to a local shadetree-type outboard mechanic and he went over it, finding that one of the coil wires wasn't seated properly into the bottom of the coil. I had replaced the wires, but apparently its a total pain in the neck to get the wires properly through the mag plate and into the coil. Anyway, the old girl lives and runs quite well - although I still have some breaking in to do on the new rings...https://www.youtube.com/watch?v=0n45NMpRagU

 

[kdiddle]

Also, it turns out that 54 year old rubber doesn't hold up too well. I put about 5 hours on the engine before the prop started slipping when trying to go faster than idle...turns out I spun my prop...and I hate to admit I didn't even know there was a rubber hub inside the prop. So off to find a replacement - I'm looking a Tacoma propeller since there doesn't seem to be alot of options for replacement.