3hp Seahorse Wants To Run Lean

[Captain Caveman]

I brought a 3hp 1957 JW-13 Seahorse back to life over the winter. I replaced the ignition, most of the lower unit, and threw in a carb rebuild. I've now run it twice in a barrel for limited periods (less than 5 minutes). It runs a little rough and doesn't run well at low or high speeds. It seems that the more I turn the knob to lean the better. In fact, I took off the knob and turned the high speed screw all of the way in - which is when it ran best. Since I only put in a cup or so of 24:1 gas/oil mix, it ran dry on it's second run. Just before dying out (while I had it running at WOT) the rpms roughly doubled before dying.

What could be causing this? Do I need to pull out the jets and give them a better clean or are there some other things that could be causing this condition?

 

[Rick.]

Re: 3hp Seahorse Wants To Run Lean

How to the ends of your needles look? if they are in poor shape the won't work worth a darn. Best of luck. Rick.

 

[1946Zephyr]

Re: 3hp Seahorse Wants To Run Lean

I don't know Rick, sounds like these are working a little too well.

It sounds like there must be fuel leaking in somewhere. What is your high speed jet set at? Those tend to run best at about 1/2 turn out.

 

[Captain Caveman]

Re: 3hp Seahorse Wants To Run Lean

At the moment it is seated all the way in. My initial setting was 1/2 turn out but it kept running best all the way back to lean. It's worth noting that I bought this motor last summer at an estate sale. It was packed head-to-toe in mouse nest material. It may have run 5 years ago but it might have been 30 years ago. Is it possible that I just need to toss this thing on my tin boat and run a full tank through to "clean things out?"

 

[nwcove]

Re: 3hp Seahorse Wants To Run Lean

not sure if id run it with the hs needle seated. when you rebuilt the carb, did you do an overnight soak, run a small strand of wire through the passages, remove the welch plug etc etc? it is odd that its happy with the hs needle seated, will it even start that way?

 

[Rick.]

Re: 3hp Seahorse Wants To Run Lean

I don't know Rick, sounds like these are working a little too well.

It sounds like there must be fuel leaking in somewhere. What is your high speed jet set at? Those tend to run best at about 1/2 turn out.

No Doubt!! I'm just thinking if the needle ends are in bad shape they will be letting fuel past even when closed. Sounds like the high speed for sure must be in rough condition. Rick.

 

[Crosbyman]

Re: 3hp Seahorse Wants To Run Lean

vent open and cleaned ?? run it with the fuel cap off to see if it will run longer

....then put the cap on the tank ... if it dies clean the 2 vent holes

is fuel flowinn down from the tank Ok ? tank filter cleaned ?

 

[Captain Caveman]

Re: 3hp Seahorse Wants To Run Lean

New tank filter. I cleaned the holes in the vent cap as well...if I remember a needle fit through there perfectly.

As for the carb clean, I didn't soak the bowl overnight. I did clean passages and remove the plug. I am starting to think that I need to pull that carb apart again. I probably missed something and I really can't remember looking at the jets closely. I only remember blowing them with compressed air, which if that's all I did, was a pretty poor job.

 

[nwcove]

Re: 3hp Seahorse Wants To Run Lean

you really need to completely disassemble the carb and soak everything except gaskets/packings/ float, overnight. then hit it with air, then a small wire through the passages, then spray carb cleaner, then repeat the air, wire and carb cleaner. then wash in warm soapy water and blow dry with compressed air. make sure the 4 tiny holes under the welch plug are clear! also make sure the new plug is seated. now you have a clean carb, ready to be put back together.

( regular pine-sol is a very good, economical, carb soak!)

 

[Scurvy Knave]

Re: 3hp Seahorse Wants To Run Lean

gosh. sure sounds like the HS needle (or seat) is worn, rounded or otherwise deformed. It is probably letting gas through even when "fully closed". You could quickly pull the HS needle and look at the tip. Personally I wouldn't run that with it turned in all the way. If you didn't clean it out properly the first time, I guess you are now learning the important lesson: any job worth doing is worth doing well.

Definitely pull the needle and check the tip. If you need to pick up a new one (and seat) you can do so when you order the carb kit.