28hp Evinrude Speeditwin Mystery - all theories welcome

[kdiddle]

Good afternoon, all. First, a quick backstory - I acquired my grandfather's old 1964 Crosby e/w a 28hp Speeditwin after his passing and set about to cleaning it up and seeing what I had to work with (https://forums.iboats.com/forum/boa...r/10556186-1964-crosby-28hp-speeditwin-rescue). After what I would consider a pretty top to bottom replacement of most everything, I continue to chase my bottom cylinder more or less not running at all.

What I've done on the powerhead so far:

• Bored .040 over and replaced pistons/rings
• Rebuilt carb with all new parts/seals
• Replaced both coils/condensers/points and set gap to .020
• Replaced spark plug wires/boots/plugs
• Replaced fuel pump
• Replaced all rubber hoses
• Replaced all engine gaskets (intake/exhaust/leaf cover/etc) along with rubber o-rings at the crank ends

At this point, I'm at a total loss as to what could be my issue. Virtually everthing has been replaced. I even replaced the coil/condenser/points for the lower cylinder today just to make sure there wasn't something wrong with the ones I had (even though I was seeing a spark). I've bypassed the cutout switch and even tried removing both grounding/cutout wires that go to the points just to eliminate them as a possible source.

Basically it will run like a champ on the top cylinder only. You can pull the bottom plug wire off and it makes no difference to how it runs, but I've confirmed that the bottom cylinder is definitely producing a spark. The plug is soaking wet and its puking fuel mix into the run bucket, so I know fuel is getting into the cylinder.

Now the video evidence:

This was from a recent test run in the water
https://youtu.be/q3Md7REdlWU

Here is proof that the bottom cylinder is getting fire, and putting back on on spark plug makes no difference
https://youtu.be/7RSLPyz9fMY

Here is it 'running' until I pull the top plug
https://youtu.be/_wp6u-UohtA

Here is playing around with the cutout/grounding wires trying to see if anything makes a difference:
https://youtu.be/0mOQyL-qcV0

I have put a small fortune into trying to get this old girl running, and the only reason I've done so is that it belonged to my granddad and I'd like to see her on the water again. If anyone has ANY theories, I'd love to hear them, as I'm about at my wits end. I cannot fathom for the life of me what's going on here. Thanks for taking the time to read my ramblings...and thanks in advance for any input you guys have.

 

[racerone]

Does primer bulb go hard , yes or no ?----Does spark jump a gap of 1/4", yes or no ?

 

[GA_Boater]

Sparks everywhere and you're chasing ignition. The second video only shows spark through the wire, not the bottom plug? Have you swapped the plugs for top to bottom?

Spark, fuel, air and compression is needed to run. Have you checked compression?

 

[oldboat1]

You might spray some carb cleaner or WD-40 at the base of the engine while running -- see if there is a change in rpm, indicating a seal issue.

An alternative issue might be a broken leaf valve.

 

[racerone]

Are those plug wires a metal core wire , yes or no ?

 

[oldboat1]

btw, would use a 24:1 fuel ratio on that motor. Champion J6J (J6C) plugs were the standard issue, and would recommend those gapped at .030. To test spark intensity, should use an adjustable open air tester (cheap -- $10 or so at an auto parts store). Look for a 1/4" sharp spark. This measures ignition output.

If spark is inconsistent, or you suspect it is, check the spring connection in the boot. You need solid core wires, and the spike has to engage the core. At the coil, the core has to engage the spike as well.

Check compression, as mentioned. Use a screw-in type tester, and pull the engine over 4 or 5 times until the needle stops moving (both plugs removed, as with the spark test).

 

[Crosbyman]

yes or no.... hard questions :frusty:

 

[F_R]

Did you check for possible water ingestion into lower cylinder?

 

[kdiddle]

Whew, I have a lot of responses to catch up on.

Does primer bulb go hard - yes

Does spark jump 1/4' - not sure. Guess I need to get a spark tester. I was only testing with a spark plug, but it wasn't shocking me through the boot. I was only being shocked when I was holding onto the spark plug while testing. But the spark being seen by grounding on the head looked quite vibrant to me.

Have I checked spark plug - yes, I've used multiple different J6C's just to eliminate plug from the equation

Are new coil wires solid metal core - yes

Does new wire engage the coil spike - yes, now it does. In my last round of ignition troubleshooting, I found my new wire wasn't seated all the way into the bottom coil, so I corrected and confirmed its fully seated. New boots were installed by me on the new wires, and I ensured the new wires fully contacted the spark plug clip.

Fuel mix - I am running 24:1 as my engine isn't fully broken in yet

Compression - I haven't checked it with a gauge since installing new rings / pistons, but there is tons of compression when spinning engine by hand (on both cylinders).

For the record, the reason I was previously chasing an ignition related issue was my clear determination that the bottom cylinder was not running and that on more than one occasion (through open water testing) I would feel the engine surge while under power (assumedly by the lower cylinder going in/out) and engine would pull hard for a split second then cut out again. That would rule out (in my opinion) anything compression/fuel related, as those items would likely be consistent and not coming/going as I was experiencing.

• Might have to try the WS40 around the base idea. That's a new on on me...
• Water ingestion? How would water be getting into lower cylinder? Through head gasket?

 

[kdiddle]

Crosbyman, I'm not sure what you mean by 'hard questions'...

 

[F_R]

So you were having this problem before doing all that work? Evidently you missed something. My suggestion of possible water ingestion came from experience. See, I once rebuilt a 30hp Johnson that had suffered severe wear. In no time at all, the motor was back with the same problem. Turned out there was a pin hole in the exhaust cover baffle plate, which I had neglected to remove and inspect ("no reason to"). Water was squirting through that pin hole, through the exhaust ports, and into the cylinder. Needless to say, I removed and inspected exhaust covers and gaskets since then.

I don't know if that is the problem with your motor, or not. Just a suggestion to think about.

 

[Crosbyman]

Crosbyman, I'm not sure what you mean by 'hard questions'...

sometimes along the yellow brick road to boating happiness suggestions are made to check abcdefg... but specific answers to each point are missing or ambiguous leaving lingering doubts as to the end and final solution of the problem.

for ex; does the spark jump .25 inches ? yes or no ? :cower:

the only real acceptable answer to that question is yes or no so I think most us contributors would like the answer to be yes or no....vibrant sound's good but it falls in the category of feelings and opinions and does not answer the question beyond reasonable doubt:indecisiveness:

As a still very young owl on this site I have eaten crow and getting wiser for it but the all real wise owls on this site really want your oldy back in the lake asap if only for the survival of the J&E species:first: .


:focus:

 

[kdiddle]

Thanks for the explanation, F_R. Regarding whether I was having this issue before all the work was done, yes and no. I did a lot of it preemptively as I knew an engine that hadn't ran in 30 years needed stuff replaced. The balance of the items were done over time as I continued chasing the fact my engine wouldn't run right. So yes, I have definitely missed something. But that's why I'm so frustrated, I've run out of things to replace and am here looking for the 'less obvious' that got by me.

I did remove both intake/exhaust covers when I had block reworked, and they all looked like they were extremely clean given the age of the engine. But I suppose there could have been a hairline crack somewhere that slipped by me. Thanks for giving me something to look at, I'll give that a shot along with getting a spark tester for the 1/4" gap requirement that appears to be pretty important.

I have another complete block that I bought for parts when I was fixing this one (parts are expensive on these old girls). As crazy as it seems, I'm about to swap the powerhead to see if it runs any better than this one. At this point, I'm pretty sure I could teardown this engine in the dark...

 

[Crosbyman]

btw .... when you wrote

I acquired my grandfather's old 1964 Crosby

what model was it ...just wondering

my venture in oldies included a Crosby Cruisette 17 footer mini cabin cruiser e/w toilet, sink with overhead water reservoir bunks (2) hence my avatar Crosbyman ​

great boat good for a 90hp yet it ran great with a Merc classic 45 in the back. got me a lot of looks smiles and sneers at the local beach

mine was the older version with wooden framed wip up cabin windows sold it to a neibhour and it is still parked on his lot :-(

http://www.fiberglassics.com/library...osbyb59011.jpg

 

[kdiddle]

Hey Crosbyman, you can see pictures of it here - https://forums.iboats.com/forum/boa...r/10556186-1964-crosby-28hp-speeditwin-rescue but I'm unsure of the model. My registration only shows Crosby as both make/model. Its a tiny 14ft fishing vessel, but it looks awful good with the Evinrude hanging off the back

 

[oldboat1]

If it hasn't been done, I would resurface the head and replace the head gasket. To resurface, use a piece of 400 grit wet/dry sandpaper on a perfectly flat surface. Rotate the cover in a figure eight pattern until it's got a uniform shine. Torque to spec with an inside-out circular pattern -- two or three passes until tight.

Nice rig!

 

[Crosbyman]

fiberglassics.com folks have Crosby boats it in the libray under fiberglass boats

http://www.fiberglassics.com/library...p?title=Crosby

yours looks great

 

[Crosbyman]

picture on mine of fiberglassics. site ..same color to !!

 

[kdiddle]

Thanks for the link to fiberglassics. it appears I have a Sea Sled. Interesting reading about the history on the 'sleds' that they were a Crosby in name only and were manufactured by another company after they were purchased. They called out these were popular fishing boats in the south which I'd have to agree with, as there were two of these boats on opposite sides of my family. This one just happened to survive from being in a garage for 35 years.

 

[kdiddle]

I think its hilarious they reference the passenger capacity at 900lbs. I can barely imagine 2 grown men fitting in this rig, much less 3 large ones.

Quick question - if anyone is interesting in answering...the fiberglassics page references FPG as construction material. What is that? I assume there might be wood underneath the floor, but this thing is solid from one end to the other. I don't expect it to be rotten from being indoors for 35+ years, but just curious if I need to ensure it doesn't rot like so many do.