'59 18hp Seahorse - STUMPED!

[Rick K]

Been having a problem with spark on my lower cylinder. Engine starts right up (half a pull and she starts to purr...), runs beautifully, can't get WOT however. Pulled the lower wire, she keeps running. Pull the top wire, she dies right out.

When I pull that lower wire, I do get a nice blue spark jumping from the wire to the plug, but not really enough it seems.

Replaced the coil front coil this evening. Other coil was replaced last season. The old one was the original, and had alot of goo, etc., on it, so I figured that'd do the trick. No go...

Compression is right up there, full tune up, etc., least season, with new plugs this season. She ran absolutely perfect until this.

I did read up on Saskatoon's issue where he couldn't get to WOT, but I'm thinking that my problem is not as in-depth as his. I can't believe the motor would run perfectly, then just start this s**t.

I did rebuild the carb, but have ruled out the fuel system with the engine dying when the top wire's pulled. Ran great with the rebuilt carb anyway.

Other than switching the coils, does anyone have any ideas?

Thanks!
Rick K

 

[OBJ]

Re: '59 18hp Seahorse - STUMPED!

Have you tried a new spark plug? Or maybe just switch the plugs and see if the problem moves to the top hole.

 

[Rick K]

Re: '59 18hp Seahorse - STUMPED!

I re-read the entire post I mentioned above, and am gonna try a few things tomorrow. It's gotta be something I overlooked.

Thanks
Rick K

 

[JB]

Re: '59 18hp Seahorse - STUMPED!

Inspect the reeds, Rick.

You have proved that you have spark on the dead cylinder and she only has one carb and good compression. Once you prove that the spark plug is good (as OBJ suggests) reeds are the most likely suspect.

 

[dave524]

Re: '59 18hp Seahorse - STUMPED!

Hello, I dont have an answere to your problem, but a question for you. I have the same motor ( 1962), did you ever change a impeler in it ? was it difficult ? Thanks for the help. Dave

 

[Xcusme]

Re: '59 18hp Seahorse - STUMPED!

Rick,
You might want to pull the flywheel and have a check of the points and gap. Check for burned or pitted points contact surfaces. Rotate crankshaft until the crank woodruf key aligns with the points rub block and check the gap. Route the coils wires so as not to rub on the cam. Remove as necessary the plug wires from the coils, reseat or screw-in wires as needed to insure positive contact.

 

[steelespike]

Re: '59 18hp Seahorse - STUMPED!

You may want to replace the plug wires your 44 year old wires may be corroded inside.

 

[Rick K]

Re: '59 18hp Seahorse - STUMPED!

FINALLY had time to tear into this beast.... Pulled the flywheel off again to check points. Perfect shape, and at .020 - they were replaced last season. Pulled the reed plate, reeds are like new.

As far as the plug wires, they were replaced as well. See, when I got the boat, the motor ran like junk, so I just took it in and had it serviced. Everything new under the flywheel EXCEPT one coil, and that was the one I just did last week.

One OTHER thing - I popped the bottom of the carb off and the float was not quite right. It's supposed to be parallel with the bowl surface, correct? It was a little low. I made it parallel, in any event. Could THIS be the reason for no WOT? I mean, it starts with a half pull of the rope, or a bump 'o the key...

Synch appears to be right on, I did the alligator clip/wire thing.

Barring any other ideas, I'm S-T-U-M-P-E-D!!!

Anybody got any?

THANKS!
Rick

 

[Xcusme]

Re: '59 18hp Seahorse - STUMPED!

Rick,
Just an outside thought.....what are the chances of a really bad lower crank seal....killing the intake of fuel to the lower hole?

I'm sure the coils were indexed to their mounting bosses, right?
You should be getting a snappy blue spark to each plug.

 

[tashasdaddy]

Re: '59 18hp Seahorse - STUMPED!

rick, the float should be parallel with the body of the ward when turn up side down. in other words when it closes the needle valve it should be parrallel. just verifing you statement.

 

[Rick K]

Re: '59 18hp Seahorse - STUMPED!

Don't know about the lower crank seal, but, when I had the reed box off, I put my light into each of the holes, and all looked REALLY clean. I have nice spark to both cyinders. I'm gonna swap coils, and change a few things around, then try her again.

I remember now, that when she first started acting up, the one cylinder would fire off an on, and I'd get a surging-type action out of the motor. That lasted a little bit, and then the cylinder died.

This has got to be something simple, or something overlooked.

Thanks again,
Rick

 

[Rick K]

Re: '59 18hp Seahorse - STUMPED!

Don't know about the lower crank seal, but, when I had the reed box off, I put my light into each of the holes, and all looked REALLY clean. I have nice spark to both cyinders. I'm gonna swap coils, and change a few things around, then try her again.

I remember now, that when she first started acting up, the one cylinder would fire off an on, and I'd get a surging-type action out of the motor. That lasted a little bit, and then the cylinder died.

This has got to be something simple, or something overlooked.

Thanks again,
Rick

 

[Xcusme]

Re: '59 18hp Seahorse - STUMPED!

You know Rick,I got to thinking, a possible leaking lower crank seal is a really long stretch as to the cause. You said that you tuned her up last season, coil was leaking and original. You now replaced the other coil and re-gapped points. Since you seem to be working with a basically original ignition with only new coils and wires, one thought came to mind. Did you replace the condensers too (even thou you state the service center replaced everything and didn't replace both coils etc)?? The tip off is your statement "When I pull that lower wire, I do get a nice blue spark jumping from the wire to the plug, but not really enough it seems. " Granted, the condensers usually don't go South, but if they are original, you could have an issue with them. As a test, swap condensers and see if the problem follows to the top cylinder. You're looking for something that's not common to both cylinders. The carb is common so it's unlikely the problem. Problems that arise suddenly usually point to something electrical.
Btw, did you try swapping (or replacing) the plugs as OBJ suggested? Describe the condition of both plugs, wet, black, tan etc.

 

[Rick K]

Re: '59 18hp Seahorse - STUMPED!

Xcuseme - My plan was to put her back together tonite (I have to pick up intake/reed gaskets) and change everything. Parts are so cheap, it's not an issue.

I did not swap plugs - maybe I should have first, but, a few others mentioned the reed issue, so I went there first. I also figured a plug couldn't/wouldn't/shouldn't be good one day, and bad the next. I have a total of about 10 hours on the engine so far this season.

The top plug was normal wear (hardly any), the bottom was clean and WET. A sure sign of no-fire. I think maybe replacing the ignition system will rule anything out under the flywheel...

Thanks

 

[Xcusme]

Re: '59 18hp Seahorse - STUMPED!

Basically reading the plugs would have pretty much omitted the reed issue. The bottom plug being clean and WET means it's getting fuel, but there's little/no ignition on that cylinder. Inspect the under flywheel parts. Coils properly mounted and indexed to their mounting bases. Points clean and set on the high side of the cam (for each set) to .020. Condensers mounted with good grounds.All connections clean, bright, and tight. Plug wires properly terminated at coils and plug contact springs making good contact. Plugs gapped to .030 (prettty sure it's .030) . Good luck and report back.

 

[steelespike]

Re: '59 18hp Seahorse - STUMPED!

Sometimes a clean plug on one cylinder can be an indication of water in the cylinder.If all else fails give the head gasket a look.

 

[Xcusme]

Re: '59 18hp Seahorse - STUMPED!

Spike, good point....I assumed wet from fuel. It would account for the 'sudden' loss of a cylinder....

 

[Rick K]

Re: '59 18hp Seahorse - STUMPED!

All fixed. Bad coil. I sit here, awaiting your ridicule. d

The bad coil was the one I replaced last year. Pulled it, as I saw just a tiny bit of oil on the mounting leg. Lo and behold, there be the crack - where it sits on the stator plate.

I just couldn't get over the "it can't be THAT part, I just replaced it" sydrome.

I of course, learned a valuable lesson....

Now, one LAST question, and I'll leave everyone alone: The cam that slips over the crank is cracked, right next to where the keyway is. It was cracked last year, and I replaced it when I did the coil.

What causes these things to crack? It's still tight on the crank and all, and I'll put another on. Torque on the flywheel is always at 40lbs.

Thanks to all for insight, advice and assistance. It's genuinely appreciated.

Rick

 

[cougar1985]

Re: '59 18hp Seahorse - STUMPED!

somebody gave me a tip last year about coils and that was that seirra coils were much better than the omc ones.i think it was paul moir if im not mistaken,but they seem to be a better quality.

 

[Rick K]

Re: '59 18hp Seahorse - STUMPED!

This was a Sierra coil....