'57 Johnson 18hp Seahorse Start problems.

[Hanr3]

Hello All,

I found this site and had to join. Tons of great info and very knowledgeable members. Thanks for a great site!

On to my problem.
I aquired this engine (FD-11, 18hp Seahorse) from an in-law. It had been sitting in his shed for at least a couple of years before I aquired it. He claims to have run it out of fuel every season before storage. I used the motor maybe 4-5 times last season, and so far about as many this season.

My biggest problem is starting.
Last year I had to turn the trottle handle as fast as it would go, and took about billion times of pulling to get her to fire up and run. This year I discovered that if I put it in forward gear and give it a little more trottle, she fires up within a dozen or two pulls. Put it runs and stays running once started. It idles etc.

May or may not be related, however it doesn't seem like the engine is hitting top RPM's. My only evidence is taht last year when it did finally wind up to top speed the boat got on plane, happened once.

Also may or may not be related. This engine is still the two hose set-up, with the primer bulb in the gas tank. I have a Johnson pressureized tank, and the bulb does prime the system. Sometimes I find that if I unscrew the tank cap to relieve pressure, reprime she starts up easier. Although that generally happens after a dozens of so pulls when I need a breather. I dont have the original hose to engine fittings and hooked the gas line direct with clamps. I guess the whole purpose of this paragraph is no fuel pump mod on the engine.

I am fairly mechanically inclined, have rebuilt a few 4L60 trannies in the past, and done a couple of engine swaps, one in a S10-Blazer and the other in my riding mower. That said, this is my first outboard engine.

I have read through a lot of thread so far, and they lead me to believe a carb issue. Does all this sound like a carb issue?

Link to my boat remodel project.
http://www.tinboats.net/forum/viewtopic.php?f=13&t=6902
I plan to spend some time fishing this year.

 

[mchin]

Re: '57 Johnson 18hp Seahorse Start problems.

I love the 18 hp omc motors, very easy to work on and easy to get parts for. Sounds like you need to do a carb re-build. I think they sell one here on iboats. There's tons of posts and a few stickies on awakening an old outboard, if you haven't read them yet, go for it.

good luck and have fun.

 

[jbjennings]

Re: '57 Johnson 18hp Seahorse Start problems.

HanL3,
If you have rebuilt automatic transmissions you are more than mechanically inclined!!!
From experience with that exact motor (one of my all-time favorites and the one I use regularly), I can tell you that if that motor has decent compression and it takes more than 2 pulls to start it, then you've got problems.
Sure, you could have carb problems. However, I ALWAYS start on a new to me motor with the ignition after I check and am satisfied with the compression. MY FD-11 has 115 psi in both cylinders, but they'll run good down to 100 or even less. 125psi is like new I suspect.
There are several threads in the "top secret files" at the top of the thread list on this forum that you should read. One is the "how to set points/change coils" which has pictures of what to do. The other is the carb. adustment thread by Joe Reeves. Others, too.
I would get good spark by testing with a spark tester---just seeing if it will cross the gap on the plug is a useless test.
Then I would clean the carb., replace all fuel lines, and replace the water pump impeller or at least inspect it for your own security.
Even in cold weather my OMC's from the 50's (I have one or two) crank on the 1st or 2nd, and if they're really feeling ornery because I haven't taken them hunting or fishing in a while, 3 pulls. Yours should, too! Having a 50's OMC that's hard to crank is just plain crazy! Here's a recent pic of "old faithful".........BTW, yes it is real electric start and it is SPECTACULAR!
But I just got e-start recently and pull started it for a long time.
JBJ

 

[56 rude]

Re: '57 Johnson 18hp Seahorse Start problems.

Electric start JB?My, arnt we living it up,lolThe 57/58 18hp johnsons have got to be one of the great motors of all time in my book,i have 2 of them but im poor so i only have pull start!Follow jb,s advise and you will hopefully have a great running dependable motor that shouldnt take more than 1 or 2 pulls at the most to fire up.My oldest a 1939 22.5 rude usually fires up after 1 or 2 pulls of the old wrap around pull start.

 

[F_R]

Re: '57 Johnson 18hp Seahorse Start problems.

Hanr3, first I agree, that motor should never take over 4 or 5 pulls at the absolute most. If it isn't running by then, there is something wrong.

You said it runs and idles after you get it started. That means that chances are great that there is nothing wrong with the carburetor---unless the choke isn't working.

But you also say that it lacks power and ocasionally picks up and goes. That says loud and clear that you have an ignition problem. It is running on one cylinder and when the other one kicks in, it goes.

Check the compression; then--
Check the choke; then--
Pull the flywheel and check the ignition--AFTER you check (replace?) the spark plugs.
My bet is that the coils are cracked.

 

[Hanr3]

Re: '57 Johnson 18hp Seahorse Start problems.

Thanks JB for the information and I will follow all of it.

Hanr3, first I agree, that motor should never take over 4 or 5 pulls at the absolute most. If it isn't running by then, there is something wrong.

You said it runs and idles after you get it started. That means that chances are great that there is nothing wrong with the carburetor---unless the choke isn't working.

But you also say that it lacks power and ocasionally picks up and goes. That says loud and clear that you have an ignition problem. It is running on one cylinder and when the other one kicks in, it goes.

Check the compression; then--
Check the choke; then--
Pull the flywheel and check the ignition--AFTER you check (replace?) the spark plugs.
My bet is that the coils are cracked.

Thanks for the sequence and I'll follow it. Not tonight though, its raining.
Couple fo questions.
Compression check- Simple to do with an electric starter, take out the plug and replace with pressure gage and crank engine over. How do you do it ona pull start? Is this a two person operation?

Choke- I gather I need to pull the carb to check the choke? If so, what are the odds that I will need a new gasket? Should I just rebuild it while I have it off?

I checked out the IBoats parts store and have several items on my wish list.
One senior respected member (name eludes me) doesn't recommend the Seloc rebuild manual, and that is the only one available. Is the Seloc similar to a Haynes auto manual? I veiw the Haynes manual is great if your just starting out, however it doesn't go into enough detail in some instances, and it doesn't always show you the best way. you will get the repair completed if oyu use the noddle and the manual.

Any prefereance between Mallory and Sierra?

 

[cc67]

Re: '57 Johnson 18hp Seahorse Start problems.

Thanks for the sequence and I'll follow it. Not tonight though, its raining.




You don't keep your motors in the house like JB?

 

[jbjennings]

Re: '57 Johnson 18hp Seahorse Start problems.

IN my defense----I don't work on 'em in the house. I work on them in my shop. But they get lonely out there and I can almost hear them crying for me late at night. That's why I keep the really whiny ones in the house. If one of them got stolen, I don't know if the thief would be as sweet to them as I am.
Anyway, my FD-11 IS on the boat and out of the house where it should be. When I get the hairline fracture on the starter bracket fixed for my '58 fastwin, I'm going to put electric start on it and I may use it more often as well. That will make room to put another couple of motors that I have been neglecting, in the house so I can keep them company.
Get that thing running, HAnR! It's wanting to go fishing.......
later,
JBJ

 

[Hanr3]

Re: '57 Johnson 18hp Seahorse Start problems.

F R,
I got to looking at the pic you posted. Lap top screen size isn't the biggest. could you confirm for me that there are 2 coils and that both in the pic are cracked?

Could someone confirm for me that I have everything I need listed.
List is going to have to wait. Something just came up.

 

[jbjennings]

Re: '57 Johnson 18hp Seahorse Start problems.

Does this help?

http://forums.iboats.com/showthread.php?t=294072

You should be able to get it running and, using a tool to prevent the wire from shocking you, pull each wire from the plug and see which wire has an effect. If you pull a wire and it dies, that wire's probably got a good coil. If you pull one and it has no effect on the motor, then that coil is probably bad. You'd probably be better off spending an extra $25 and replacing them both, even if only one is bad.

JBJ

 

[tmcalavy]

Re: '57 Johnson 18hp Seahorse Start problems.

Good advice so far. You don't have to pull the carb to check if the choke is working. Take the choke knob/pull off and make sure the butterfly in the carb throat closes when the choke is out. You should be able to start that puppy with 3-4 pulls when it's cold by laying the throttle over to Fast, choke out/on, and pulling the rope...if both coils/wires/plugs are any good. Spend some time on it and it will reward your efforts...great motors.

 

[Hanr3]

Re: '57 Johnson 18hp Seahorse Start problems.

Hey Jb,
great write up. Looks almost identical to my Briggs & Straton procedure. About the only difference is the coils. .20 gap, and .30 plug gap. Thanks,

I think I'll replace everything.
Sierra 18-3377 Water Pump Repair Kit
Mallory Carb Kit 9-37106
Sierra Ignition Tune Up Kit
Mallory Ignition Coil 9-23102
Mallory Seal Kit, Gear Housing 9-74105

I have to figure out the plugs and plug wires yet.
Any recommendations.
I think I'll order everything from IBoats too.

Am I missing anything on my list?

 

[Hanr3]

Re: '57 Johnson 18hp Seahorse Start problems.

Good advice so far. You don't have to pull the carb to check if the choke is working. Take the choke knob/pull off and make sure the butterfly in the carb throat closes when the choke is out. You should be able to start that puppy with 3-4 pulls when it's cold by laying the throttle over to Fast, choke out/on, and pulling the rope...if both coils/wires/plugs are any good. Spend some time on it and it will reward your efforts...great motors.

Thanks! I'll check the choke out when I rebuild the carb.

 

[Hanr3]

Re: '57 Johnson 18hp Seahorse Start problems.

Update.


Well its been a year since my last post to this thread.

I'm still haveing trouble with the engine.

I replaced all the electrical last year. She still doesnt run right and is hard to strart.

I bought the stuff to replace the carb, water pump etc.
I think my performance issue was the original cork float, its was flaking pretty well. I bought a replacement today, plastic, and cleaned the **** out of the carburator. Carb back together and ready to be installed.

However now Im having trouble with the engine turning over, as in it wouldn't budge more than 1" or so. I pulled the lower unit off to replace the water pump, figuring my stuck engine may be related to teh lower unit, nope.

I pulled the strarter rope assemble, pulled the flywheel, loosely put the flywheel back on and she spins great by hand, spark plugs removed. I can watch both pistons make full travel. Mental note, seafoam for carbon build up on pistons.

I got to thinking why would the flywheel get hung up? The only thing for it to hang up on is the coils, they havent moved since last year, or did they. Nope still screwed tight to teh assemble, however that whole assemble moves, turn pretty easy. Is that normal? ITs supposed to turn with the trottle handle, however it will turn on its own too. Plus side to side play. Thinking Im missing a part or one is worn out.

I pulled the 4 screws that hold the electrical plate (dont know what else to call it) to the engine. I see there is a brass colored plate with 3 screws and an aluminum plate under it. The brass plate holds the aluminum plate in place, yet allows it to spin. The aluminum plate is attached to the electrical plate.

I removed the brass plate, and noticed the aluminum plate is notched for a key hole, however I dont see anything for the keyhole to line up with, am I missing a part? Is there a part that goes between the aluminum plate and the crank bushing?

 

[sluggo99]

Re: '57 Johnson 18hp Seahorse Start problems.

I'm not an expert by any means, but I had the same puzzle about the notch on that bushing. It's apparently not for anything, other than maybe the manufacturing process. Careful about how the bushing goes on, btw. Flat side up as I recall.

 

[Hanr3]

Re: '57 Johnson 18hp Seahorse Start problems.

Update.

Compression
95 top piston, 110 bottom piston.

Bought a used carb, rebuilt it, and the motor strats like it should, idles much better, however Im 95% sure I have an ignition problem.

I also syncronized the engine/carb.


Max speed is only 7.3-7.5mph. I believe both coils are working, although something isnt right.
Reason I say both coils are working is I bought a cheap ignition tester from HB, kind with a light bulb, it lights up when I pull crank the engine for both spark plugs.


Last weekend out, I had a spark plug wire get a hole wore through it. Engine run at a reduced speed, 4.5 mph. Try to go any faster and she would get real sluggish. Wondering if that is the only plug firing?

On one hand it seems both plugs are getting juice, yet on the other hand, it seems like one piston isnt firing at the right time, or at all (based on top speed).

Not sure if it matters, however the slowest I can idle down to is 1.6-1.7mph, and again top speed is 7.3-7.5mph. Does that sound like an engine running on one piston?

looking for some ideas, Help.

Thanks.

 

[FHB]

Re: '57 Johnson 18hp Seahorse Start problems.

I have the same motor in 10 hp. I am a newbie at this and have limited insight.

However, I inverted my spark plug wires once and nearly the same thing happened. You might switch them and see what happens.

I think my sparkplug wires dated from the Nixon Administration. I replaced them which requires taking off the flywheel and the plate. You need solid core copper wire and not the usual graphite ones. Advance Auto has them in the hi performance wire section.


Good luck with your 57 Seahorse!