1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

[aborgman]

Pulled flywheel, adjusted timing/points, re-gapped plugs - now getting good spark.

Motor fired up with some starting fluid, but wouldn't run. Noticed gas leaking out front of carb.

A carb rebuild later (all new gaskets, new float, new float needle/seat)...

...and it's still has gas leaking out front of carb. Not a lot of gas, but enough for a drip every couple seconds off the bottom of the float bowl. Got it to run for a while in the bucket last night, but -

1) It seems to be running really rich from what I can tell.

2) It's still dripping gas.

3) It will only run at about 3/4 throttle (throttle position for starting) any more or less throttle and it just wants to die... and even when it is running at 3/4 throttle the RPMs seem WAY lower than they should - full throttle should be about 4000RPM on this motor.

4) Still doesn't want to start without a little starting fluid.

5) Seems to be running a little hot, so even though it is peeing water I'm not sure what state the powerhead water passages are in... So I guess I get to pull that apart next. How hot is acceptable at the cylinder head? It's certainly too hot to touch.


I'm at a loss on the carb/starting issues at this point - it really doesn't make ANY sense. This is probably the most simple carb I've ever seen (even more simple than the one on my old VW Microbus) and everything that should cause this problem (bad needle/seat/float/gasket) has been replaced. Everything looks good - the carb isn't full of varnish, all the passages are open, no cracks in the pot metal... The only possibilities I can think of are:

1) the missing air pre-silencer and its "low speed needle stop" - but even that doesn't make any sense because if the needle is screwed in too far it should be running too lean, and not too rich...

2) Leaking air through the expansion plug - but again that should cause a lean condition, not a rich one...


Any ideas/suggestions?

 

[rickdb1boat]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

Is it doing any sneezing at idle? Have you checked the reeds? Is the float level with the carb body when inverted? As for overheating, If it's too hot to touch, then it's definitely running to hot. Was it run in saltwater or fresh? Below is a link you may find useful....

http://www.outboard-boat-motor-repair.com/Evinrude%203%20HP%20Lightwin%20Outboard%20Boat%20Motor/default.htm ] Click Here [/url]

 

[Drowned Rat]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

You replaced the needle packing I assume. The nuts holding the packing in place should be just tight enough to give the needles some resistance when turning. If you got a carb rebuild kit, it comes with packing rings that look more like washers than packing material. I've found it takes more pressure on the packing nut with these newer style packing washers than with the older stuff.

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

Is it doing any sneezing at idle?

Not that I noticed.

IHave you checked the reeds?

Yes, they look fine.

IIs the float level with the carb body when inverted?

Yes.

IAs for overheating, If it's too hot to touch, then it's definitely running to hot.

Pretty much what I figured - although I did read somewhere temps up to about 150F are acceptable, and I'm pretty sure 150F is too hot for me to touch...

IWas it run in saltwater or fresh?

As far as I know fresh water only.

IBelow is a link you may find useful....

http://www.outboard-boat-motor-repair.com/Evinrude%203%20HP%20Lightwin%20Outboard%20Boat%20Motor/default.htm ] Click Here [/url]

I've been using that site quite a bit...

--
aborgman

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

You replaced the needle packing I assume. The nuts holding the packing in place should be just tight enough to give the needles some resistance when turning. If you got a carb rebuild kit, it comes with packing rings that look more like washers than packing material. I've found it takes more pressure on the packing nut with these newer style packing washers than with the older stuff.

Yeah - both pairs of needle packing, new float chamber to carb boss gasket, new float/float needle/needle seat, and new carb to float body gasket as well. Packing nuts are tightened to the point where the needles are just barely finger turnable.

--
aborgman

 

[Drowned Rat]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

Those packing nuts are the only thing keeping fuel from coming out around the needles. Getting all the old packing material out can be difficult sometimes. Material left in the carb body could cause the new stuff to not seat correctly. How many packing rings did you put in each one? My book calls for 4 rings on the high speed needle and 2 rings for the slow speed. I've seen rebuild kits come with only 4 rings total. You could try adding another ring or two to the needle that's leaking.

 

[tashasdaddy]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

check this out.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=28;gtid=818798;gpid=818802

 

[Drowned Rat]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

One other thought is fuel is leaking around the threads of the packing nut itself. Some may disagree, but you might try putting teflon tape on the packing nut threads and then installing it.

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

Those packing nuts are the only thing keeping fuel from coming out around the needles. Getting all the old packing material out can be difficult sometimes. Material left in the carb body could cause the new stuff to not seat correctly. How many packing rings did you put in each one? My book calls for 4 rings on the high speed needle and 2 rings for the slow speed. I've seen rebuild kits come with only 4 rings total. You could try adding another ring or two to the needle that's leaking.

I've got 2 rings in each, but it isn't leaking out around the needle. It is leaking right out the air intake.

--
aborgman

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

check this out.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=28;gtid=818798;gpid=818802

Yeah, that is the adjustment procedure I plan on using should it ever run well enough to actually let me do so,,, right now it won't run anywhere other than at the start position on the throttle - try to lower the speed and it dies, try to increase the speed it dies.

--
aborgman

 

[itstippy]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

What do the compression readings look like? Those lil 3HP motors are gems but with the tiny cylinders they are very susceptable to breathing problems when the compression gets low. They become hard to start and to keep running if they do start. The suck-squeeze-bang-puff don't work right. The suck part may not be sucking hard enough to properly atomize the fuel and inhale it into the crankcase. That would cause fuel to dribble and puddle instead of doing what it's supposed to.
Check the compression, anyway.

 

[tmcalavy]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

I believe your post on doing a thorough carb cleaning. If it were mine, I would recheck/clean the needle/seat and if that doesn't do it and the packing nuts are tight, I would re-install the old float and needle/seat (if still usable) just for grins. Carb kits can be too generic sometimes. If that doesn't work...????

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

What do the compression readings look like? Those lil 3HP motors are gems but with the tiny cylinders they are very susceptable to breathing problems when the compression gets low. They become hard to start and to keep running if they do start. The suck-squeeze-bang-puff don't work right.

I'm a little suspicious of that... I haven't had a chance to throw the compression tester on it yet. I'll try that sunday when I have access to a compression tester.

--
aborgman

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

I believe your post on doing a thorough carb cleaning. If it were mine, I would recheck/clean the needle/seat and if that doesn't do it and the packing nuts are tight, I would re-install the old float and needle/seat (if still usable) just for grins. Carb kits can be too generic sometimes. If that doesn't work...????

Well... the reason I replaced the old one was because it was doing the same thing. I'm going to tear the carb back down and take a look again though... I'm a little suspicious of the float chamber to carb boss gasket - even though it is new... seems like the only way for gas to be getting up from the float bowl.

--
aborgman

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

As for overheating, If it's too hot to touch, then it's definitely running to hot.

The impeller looks great and it's definitely pumping water. I pulled the powerhead, and the water passages from underneath look pristine, and air blows freely through all of them... I wonder why the heads are getting so hot?

I didn't really want to pull the heads - but it's looking like I'll have to.

--
aborgman

 

[tmcalavy]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

Got to thinking about your carb problem. A similar vintage Johnson, the LT-10, has a hex-head plug on the bottom of the carb. It functions as a plug and as a flow-back valve to keep the carb bowl from overloading. Check your carb. If it has a similar plug, remove it and make sure all is clean in there...if no plug, obviously not an option for your problem.

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

As for overheating, If it's too hot to touch, then it's definitely running to hot.

The impeller looks great and it's definitely pumping water. I pulled the powerhead, and the water passages from underneath look pristine, and air blows freely through all of them... I wonder why the heads are getting so hot?

I didn't really want to pull the heads - but it's looking like I'll have to.

So I pulled the heads - everything is beautiful. Not a single clogged passage or slightest bit of gunk. Blew water through it and it flows great. I have no idea why the heads were hot... the only thing that makes any sense would be it not getting enough flow through the holes in the head gasket:

http://www.outboard-boat-motor-repa...Outboard Boat Motor/images/3012 parts pg5.jpg

All the inlet and outlet passages are actually in the cylinder/crankcase itself, and it appears that just the water pressure is supposed to circulate water through the small holes in the head gasket to actually cool the head.

--
aborgman

 

[Chinewalker]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

The heads on the 3hp models do tend to run a little hotter than others as there are minimal cooling passages through them - just a routed channel around the outer edge. The exhaust covers also run hot for the same reason. As long as the cylinder block is staying cool, you're good to go.

Before you reassemble to carb, invert it with the float and needle in place. Blow into it gently and see if the float needle is stopping the air. Not a perfect test, but you should be able to get an idea as to whether the needle is doing its job.

- Scott

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

The heads on the 3hp models do tend to run a little hotter than others as there are minimal cooling passages through them - just a routed channel around the outer edge. The exhaust covers also run hot for the same reason. As long as the cylinder block is staying cool, you're good to go.

After pulling it apart I'm not too worried - the water passages all looked great.

Before you reassemble to carb, invert it with the float and needle in place. Blow into it gently and see if the float needle is stopping the air. Not a perfect test, but you should be able to get an idea as to whether the needle is doing its job.

It is - the new needle is definitely seating/sealing ok. We'll see if it is still leaking the evening when I get a chance to run it.

--
aborgman

 

[aborgman]

Re: 1952-54 Johnson Seahorse 3HP (JW-10): Carb problems and other issues

:''''(

Ugh....

I'm ready to just give up on this thing. I've had this carb apart a dozen times, and everything looks great...

... but it still leaks gas right out the air intake, and it still won't start - except once every 30 pulls if I spray it with some starting fluid - and on the rare occasion that it does start, it doesn't seem to want to run for long.

On the latest run it did run long enough to let me attempt to adjust the high speed needle. Of course then I tried to drop the throttle down to the slow setting to adjust the low speed needle and it died... and of course wouldn't start again no matter the amount of pulling or starting fluid.

I'm about ready to take this thing to the junkyard, but I need a motor - can't afford a good used one, and I'd have to sell my kids into white slavery to afford a new one.