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1958 Johnson Seahorse CD-15 hard to start after running.

C

CD-15

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Rebuilt carburetor, changed points, condensers and coils and the engine runs fine but after I run it it is very hard to restart. I have loosened the gas tank cap to remove pressure and that seems to help. Seems to be flooded after it has run.
Thoughts?
 
There is no reason to loosen the cap.----Does spark jump a gap of 5/16" , yes or no ?-----Is float level set correctly
 
So the plugs are gapped at .030 and are you thinking that the float is not stopping the flow when the bowl fills?
 
I don’t think I understand the 5/16 spark. I’m getting a nice blue spark but don’t know about the spark jumping a gap of 5/16.
 
That wonderful magneto can put out up to 28,000 volts.-----It does not take that much to jump a gap of 0.030"-----But it takes more voltage to jump a 0.030" gap in the cylinder when air is compressed.----So you might see spark on a plug laying on the block.----And have no spark in the cylinder.----So most of us test the maximum voltage output !----Condensers can also fail when warm.-------Perhaps this helps you.
 
Excellent, Racer. Spark color can also be a sign we can learn from. We want a nice crackling white/blue spark. I like to see 3/8" on these older magneto motors. Question! Can't these tanks build excessive pressure if they are out in the hot sun? Yes? No? If that pressure exceeds the limits of the float valve to hold that pressure......then what?......or does the check valve in the air supply line simply bleed back air into the crankcase when that pressure is too high?.......or am I expecting too much for this primitive engineering? If my memory serves me correctly, they built the SR71 Blackbird in 1963. Why do I bring that up?........ It's still the fastest and highest flying airplane ever built. Very interesting!
 
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Thanks for this info. Back to my garage to do some more testing. This motor is 62 years old and I am 71. I’m hoping to keep it running as long as I’m running.
 
You may need to look at boyancy of float and/ or it's needle and seat......also float level......not holding back pressure at rest. Try to partially tilt motor forward while drifting or parked. This will let excess fuel drain away. If this makes a positive difference then we know what's happening.....it's fuel related. That motor....in good hands, will outlast all readers here on this forum.
 
Good question. If you read this forum.....you know what I suggest....see above in fuel/mixture threads. I still regularly run my old "wallhangers". Finishing 1963 5.5 Johnson restoration right now.
 
If you are to run these older motors at the 50 to 1 ratio, is there a recommendation for a different heat range spark plug??
 
Sorry for the late reply - fuel mix 24:1. And related to the float - when I rebuilt the carburetor the kit I used had a pin that connected to the float hinge with what seemed to be a flimsy wire clasp. Maybe it is fine but I thought at the time it didn’t seem strong enough. I recently rebuilt a lawnmower carburetor and the pin/float mechanism seemed much more substantial.
Thanks for everyone’s input. As you can tell I’m not a mechanic but am really enjoying working on this old motor.
 
The pin for the float is held in place by the float bowl I believe.----There is a spring clip / wire thing that pull the float valve off it's seat when float drops.----Pictures help.
 
Note to Bobby, normally no change in heat range for plugs. Working on a QD10 now.....probably drop to a J4J in this baby. I expect these motors to last almost forever. Mr Scott thinks I belong in the 50's......you know, he's right! Should see my collection of 1959 Golden Anniversary Evinrudes. Got em all from the 3 to the 18. Evinrude lasted 111 years. Pretty sad, but gotta admit the Japanese make a pretty good motor too.
 
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Evinrude is not gone.-----Evinrude stopped making big 2 stroke motors.----They are now developing the GHOST PROJECT as we speak.----Perhaps it will be a HYBRID unit of some sort with no motor visible on the transom.
 
Bombardier bought bankrupt OMC in 2001. I personally think the e-tech was a poor motor, contributing to the failure. It is obvious that BRP (Bombardier Recreational Products), is a leader in other areas.......no point in battling within the outboard arena. The Japanese equipment may eventually wipe off Mercury too. The Yamaha company is so very diversified, unlike Mercury. They now have a 25 hp 4 stroke at only 125 pounds......besides, how many motors do they make for Mercury already? Tohatsu and Honda are now basically one after years of working together. Suzuki has always been a good product. The country that "invented" the outboard has gone Japanese.
 
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Hi....sorry. In my post #13, I directed you to the fuel/oil mix threads here at Evinrude/Johnson. You can believe me on this..... I will never ever lead you wrong on mixing ratios. I have 55 years experience at operating 2 stroke outboards in remote locations of Canada. Been using Amsoil 100:1 pre mix for over 42 years. For bushing motors....such as yours....I run 100:1 Amsoil Saber BUT MIXED @ 50:1 with NON OXY FUEL. When 1965 rolled around for OMC, then bearings became standard. Then 64:1 (2 oz. per gallon). In my trolling motors I've stayed with 100:1. ALL my chain saws......I sell firewood.....also 64:1. The 30's in the background are 1988's. They have always been mixed 100:1 and used for freighting. I CAN ONLY SPEAK FOR AMSOIL PRODUCTS. I "walk the talk"......always have. Can't speak for what others think or tell me until I prove it myself......then I will pass it on.
Thanks Rook!
 
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