1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Portagee1

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Hello world,

After reading thru the forums, I decided to join. Anyone who has experence on my RDS-23 I would greatly appreciate it. I will list the chain of events as complete as possible and let me know your thoughts. Thank you in advance.

I have owned my 1971 StarCraft Arrow 14ft fiberglass runabout for about 20 years. About 10 years ago a 1961 Johnson Seahorse 40 for it (i like vintage stuff) and it came from a private collector, he said it never ran. The bonnet (hood) was stolen which stinks because it was a fully loaded hood with all the Gold insigneas and all, I found a replacement but it was a brush painted cover that looks like it was brush painted. When I got the engine intially I pulled the cylinder head then when it first ran, it ran rough and found the cylinder walls just as new as new could be. Found out the coil was bad and replaced them and this engine ran like a top for 5 years (self employed so maybe 10hrs a summer tops fishing, stored properly every winter). Moving fwd I had to moth ball it 5 years ago due to a divorce and this weekend I started to play with it: I put it in a large tub of water and she would not start, it turned over, just would not pop. After a few times pulling the flywheel to check the points, I cleaned the points really good and it ran. I had problems with the flywheel key and thanks to a thread from 2006 here, I got the p/n and bought 5 new keys Monday morning ( what can I say, I like to be prepaired). With a new water pump installed and fresh lower lube; I dropped it in the water today. It acted like it was dropping a cylinder and was trying to come back but never did. I ran it just off idle for about an hour on the boat in the river. If I gunned the throttleafter extended idle travel it reved up almost like old times, but broke down again to an idle. Idle too is rougher than I remember. This engine allways was a quick start and ran strong.

My first thought was a dirty carb. Sitting all those years has to be bad...So I pulled the carb, disassemble it WOW! it looked brand new (when I moth balled it, I spared no expence When I did 5 years ago), so very, very clean. The only issue I could find was the low speed screw packing was trashed (while running, adjustments had no effect). Now I need a carb rebuild kit for that one packing seal. Ok, so I then removed the fly wheel again, the points look good and so do the coils. I pulled the plugs and the top cylinder is wet but looks new. (i installed new plugs before todays run so they were fresh) The bottom cylinder is black soot but dry. I'm thinking I am dropping a cylinder due to lack of spark or a bad coil. I tried to disconnect the black wire off the points going to the vacumme pod on the left side of the engine facing forward and the other black wire going to the key switch on the other side while on the water. That had no effect. (My thought that it was dropping the a cylinder thru a shorted to ground contact) Also, When I removed the flywheel the brand new key looked shot. My flywheel is awsome but the keyway has a bit more play than I care for. I would buy a new flywheel but finding one with a starter ring and generator belt cog is very tough. Monday I bought a new set of points and condensors, I want to install them with new spark plug wires tomorrow. How about coils ohm out check ok but still be bad? Yes mine are actual Johnson Coils and not a set of cheap copies. I'm slowly paying for the dealers second home in the islands> :) with part bills. The two smaller black wires comming from the points where should they actually go? With so many times this thing has been removed, even I am confussed. The spark from each coil hot or cold will jump a 1/4" gap. Also is there adjustment on the coils to the flywheel? I've seen point specs but not one for magnitos (coils) to flywheel gap.

1961 Johnson Seahorse 40
RDS-23 Model#2166431
Fuel 93 oct Johnson XD-50 oil at 50:1 ratio
Compression is about 100psi no diffrence adding oil to the test.
No backfire or popping. (reed check)

My background: I have been working on small engines since I was 12 as a way to make pocket money as a kid. I was a Master GM Auto and truck Technician, ASE Master Auto, Medium duty and Heavy Duty Truck Technician Gas and Diesle and have owned my own equipment repair business for 17 years. Not to brag, but I am a very fourtunate individuals to see and work on alot of engines over my 42 years. Sometimes even the best get stumped and that where I am at now. Very sad because I want my boat running for this weekend and I know this is a simple fix. I just need help finding the simple answer.

Thank you for your help in advance.
 

Daviet

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Just a quick thought, does your fuel pump pulse off of the upper cylinder? With the upper plug being wet and looking new, I wounder if you might have a defective fuel pump diaphram and flooding the upper cylinder with gas.
 

Portagee1

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Daviet,

That is an intresting question: I will go check....

Ok I am back, and the fuel pump pulls from the lower cylinder. :(

That was an awsome idea to check that, Thank you for the energy!
Joe
 

Daviet

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Well, that ansewers that.
Have you checked the spark with an air gap tester, will the spark jump a 1/4" air gap and is it bright blue?
The condition of the plug seems to indicate the upper plug is not firing.
 

Portagee1

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Yes, Sort of. I use the old method of a #2 phillips screw driver and holding it about 3/8" to 1/4" away from the head bolt while a friend cranks the starter. It is blueish yellow. loud snaps too. the upper cylinder is the same but not as strong. I am wondering if the points and condensor have soaked up moisture over the last 5 years. My gut keeps telling me it is coil or spark plug wire related. I have the new points so I will put them in anyhow. The ones in there now is a factory set, with very few hrs on them... just 10 years old.

Joe
 

Daviet

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Make sure that there are not any cracks in the coil and you might also check the plug wire where it screws into the coil, maybe even cut 1/2" off of the wire to make sure there isn't any corrosion in there. Make sure the contact area where the points mount to the mag plate is clean so the points get a good ground.
 

Portagee1

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Over the weekend when I had the whole plate off I checked the coils for cracks and ohms. The plug wires however did not come off. What should the plugs look like? Two stokes run very diffrent than 4 stokes. Should the lower be dry with a light coating of black soot?

Joe
 

yorab

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Hi Portagee1. Pick up a spark tester at any autoparts store for less than $10. Then you'll know exactly how strong your spark is. I'm not sure what gap yours should be jumping, but on my '63 75hp (battery distributor ignition), it's recommended that the spark jump a 7/16" gap. You can also try to pull a spark plug lead while the motor is running. If there is no change when the lead is pulled, then the cylinder wasn't firing.

Dan Gano at ganotech.com may have the packing washers that you need without buying the whole rebuild kit. Give him a call.
 

samo_ott

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

You can buy the packing nuts (washers) at any OMC dealer fr $2 each or so.
 

Portagee1

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

KFA4303, Thank you for the info. I found the book most helpful. The link to that artical was informative but there is no page #3. It was helpul on how to se the coil (magnito) to flywheel gap. I'm glad I read that because it has been a thorn in my side.

Any idea how to retapper the keyway groove? I have seen a link in old threads about how and the reciepient of the info is most pleased. Sadly Paul Moir who was posting the link to help has a full mail box. The link goes no where now. :(

Sam_ott: I will visit the dealer today for that packing, Thank you.

yorab: I tried the pull a spark wire while running. It was scary as having been "bit" by the spark before let alone hanging off the back of the boat with river current flowing. Those engines sit behind themselves quite far. Needless to say, it did not make much diffrence but it di. It added to my frustration.
 

tx1961whaler

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Let's go back to basics.
Compression is OK at 100 psi even.
1/4" spark using a spark tester is good with this magneto. Are the coils in good condition (no cracks)? I usually just replace all of the ignition parts (coils, wire, boots, plugs, points, condenser) for about 80 bucks to get away from endless troubleshooting.

The carb really needs to be spotless. Soaked in cleaner, sprayed through all passages with cleaner and compressed air, carb kit installed. Pay particular attention to the tiny holes under the welch plug on top of the carb. If they are clogged it won't idle. Also the main jet in the carb bowl needs to be spotless. I run heavy monofilament fishing line through it to clean it and also use spray cleaner.

The flywheel absolutely needs to be torqued (with a torque wrench) to 100-105 ft-lbs to prevent the key from shearing. A strap wrench helps to hold the flywheel.
 

Willyclay

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Rubixone

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

I have this same motor sitting in my garage cause I too enjoy working on them, they are super simple, I read every ones post, and there is a lot of good info but a little off track so let let me give you some simple trouble shooting tips, first pull the fly wheel and change the points n coils since you have the kit, gap your points to .3, second pull the coils and get a cheap light tester and a 12 volt battery connect the plug wires to just the battery, the light tester and see if the wire is good(assuming you have not put your new wires in if you have omit that step), while the coils are off grab an ohm tester and set it to 200 ohm or your lowest setting, you should put the red lead on the tester on the part of the coil that the spark plug wire goes into and the black lead to the ground wire coming off the back of the coil and you should get a reading from 1.3-1.6 this is the average however I have had coils that ohm out at .6 and 1.7 and still work but not for long they go eventually. but honestly the fact that you have spark really sounds like your points just are not set... happens a lot... I'd bet money on the points, you do understand how to gap points right??? if you have email address you can pm me and I'll send you a really basic manual for that motor it's a couple files that really helped me...
 

Willyclay

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

, gap your points to .3,

With all due respect, I believe the correct ignition point gap setting should be .020inch, according to every reference I have looked at for the RD series motors. It would not be the first time I was wrong, so let me apologize in advance if this creates any confusion!
 

Willyclay

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

Also is there adjustment on the coils to the flywheel? I've seen point specs but not one for magnitos (coils) to flywheel gap.

The coil faces should be flush with the machined bosses on the armiture plate. Refer to page 51 in the manual I linked you above. Forum guru F_R has a special tool for doing this and he might share a picture with you if you PM him.
 

Rubixone

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

yeah I was off my bad... i looked and chart in book and flywheel to double check it is definitely .2 Good catch Willy, I don't know if you remember but you helped me get this same motor running back in 2010, so thank you for all your help, even though this isn't my thread.
 

samo_ott

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

You mean .02!
 

Willyclay

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Re: 1961 Johnson Seahorse 40- Newbee -Runs rough heres my story.

I don't know if you remember but you helped me get this same motor running back in 2010,

Glad to have helped and now let's all see if we can get the OP going by this weekend like he hoped! I agree with him that it is usually something simple. The trick is identifying it. Another member reported having a bad set of ignition points new out of the box that just about drove him nuts. In my case, it was crud in the low-speed carb jet that defied three cleanings. I finally got it out with a dental pick and my RDSL-21 was great from then on. Let's get all hands on deck to help this new member. A belated "welcome aboard" to him!

EDIT: While your compression numbers are great, any chance one/both compression relief valves may be slightly out of adjustment and leaking when that old beauty is under load off idle? Just a thought.
 
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