Johnson Seahorse 5.5 CD-12 restore

Some history
I got this CD-12 with the purchase of a new house. The motor probably sat for 10 years since the previous owner didn't seem to know anything about it and he had the house for 10 years. My son and I have been working to restore it since august. We have replaced all the gaskets, rebuilt the carburetor, converted from the pressure tank to the fuel pump, changed the impeller, changed the gear oil (which by the way looked and smelled like dog vomit). We have it running at throttle up.

Problems 1) The engine will not run at idle speed. We can get it running when it is set just above start on the throttle handle and then taken to high throttle right a way. It will run for a little while maybe a minute and then starts to bog down. And if you go towards idle or throttle down it will start to die. 2) It is extremely hard to pull start. I am 40 years old and in good shape and I have to pull with all my might multiple times before it will start. 3) There is a hole in the lower end above the prop that looks like it is supposed to be there. It is the size of a small nail maybe 1/16" diameter and leaks gear fluid when the engine is running and for a day afterwards. 4) The carb bowl needs a new gasket and filter. I have a solution for this from vintageoutboard.com.

In speaking with vintageoutboard he suggested there is something binding up either in the power head or in the lower unit. So I pulled the power head off and I can turn it easily. So my thought is it is in the lower unit. The shifter was in neutral and I was turning the drive shaft is very difficult. I expect there is a problem in the low end but I am unsure how to troubleshoot it. There is a lower end on sale on Ebay for $95 and I am wondering if I should buy that. The low end of this unit is pretty banged up. Any advice is appreciated. Thanks

You can run the engine without the gearbox for short spurts. Did you replace the head gasket?

The gearbox is real simple it is a 1955 you need to remove the powerthead to disconnect the shift link in order to drop the gearbox. Then just take it apart and see what the guts look like. It may just need a good reseal and some new crank seal for the powerhead. You can probably get most of the parts at seaway marine in lynnwood WA just give them a call once you find out what it needs. I believe the gearbox has no bearings just bushings and thrust washers for the propshaft and driveshaft. Good luck on finding a parts diagram with part numbers your on your own.

Have you checked the drive shaft shock absorber spring.I believe this model has one.If it breaks it can make starting very hard.There are fixes for it including welding.I am sure someone will come in with more info on this.Apparently it is a fairly common problem.

kimcrwbr1 - I have not tried running it without the lower unit, but I can do that. I have had the lower unit off and the drive shaft disassembled. I did not see anything really bad except the gear fluid/oil was really bad (looked and smell awful). I reassembled and resealed with new spaghetti gasket and 3M 847.

flywheel75 - I think the spring is fine. At least the spring at the connection of the power head to the drive shaft is fine.

If I pull the power head and have the lower end in neutral, should I be able to turn the drive shaft?

The drive shaft section below the water pump is called a shock absorber. It has a heavy spring inside that sometimes breaks and jsms up the lower unit. And/or it may simply be expanded from dredging rocks. What you need to do is remove it and clean out the inside real well, then peer in there and see if the spring is broken. If not broken, just beat or press it back together and go ahead and run it. Some people weld them if broken, but care must be taken not to get them out of alignment.

Just for a frame of reference...These motors were among the best motors omc ever made. They start easily, idle perfectly and are extremely reliable. If it's not as described, something is wrong. What gas oil ratio are you using???

If it won't idle in neutral, I doubt it is in the lower unit, although there may be a problem there that needs fixed or replaced.

I was never able to get mine to run with the fuel pump conversion. It runs like brand new with the pressurized tank, but ran like crap and wouldn't idle with the fuel pump conversion. I switched it back and have used it for years. Hope this helps.

I am using a 24:1 ratio for the fuel mix. I have the old pressurized tank but it is shot. The lines are shot and there are multiple holes in the tank.

I had taken the power head off the lower, the pull starter off and the plugs removed and the fly wheel turns with little effort. If I put the plugs back in and the pull starter back on, I have to yank on it pretty good. I had tested the pressure and got 90psi for each head. I haven't tried to run it without the lower yet. I am starting to wonder how much more to sink into this thing. I already have around $200 with tank, fuel lines, fuel pump, gaskets, etc. Plus need to fix the lower end leak yet.

Well, in my opinion these are wonderfull motors and will outlast some of the new motors made today.-------------------But it has to be in good condition now and you have to be able to maintain these simple motors.-------------Not much plastic in these motors !

Anyone have ideas on what can be causing the hard pull start? I want my son to be able to pull start it but that is definitely not the case now.

I'm thinking a problem with the recoil starter.....can it be rope started easily??? The rope start grooves are built into the flywheel. Meanwhile, here is a complete 3 part rebuilding guide for that specific motor:

http://www.duckworksmagazine.com/03/r/columns/max/11/index.htm

If the flywheel is turning fairly easily by hand now that you have it disconnected from the lower unit you have narrowed it down a whole lot.

Is the 'recoil starter' the spring in the pull starter? When you say can it be started with a rope easily, I assume you mean get a rope around the flywheel and try to start it that way vs using the pull starter.

From follow up research, I should not be able to turn the drive shaft easily with the impeller. I will focus on the power head first and move to the lower.

The best way to adjust the points is with a timing light especially on the small two cylinder engines. Use a spark gap tester and it should jump a gap of at least 1/4 inch brite blue snap. Use any 12 volt battery and point the timing light at the two marks on the outer edge of the points plate. the single mark on the flywheel needs to be inbetween the two marks. If you pull the flywheel make sure you torque the nut to spec before you fire the engine up. It makes it nice you can adjust the points without pulling the flywheel. Once you get it timed properly check adjust engine sync between throttle opening and spark advance is very important also. Then you can focus of fuel delivery. As long as the single fuel line upgrade was done properly there should be no problems there at all.
http://leeroysramblings.com/Converting_dual_fuel_line.htm
There are a couple was to do it that work just fine.

Maybe I missed it, but have you checked that spring in the lower unit yet ??

I have not had the chance to check the lower unit yet. I hope to this weekend. During the week is tough with family activities.

I am confused. Why do I need to check the timing? It runs throttle open but will start to bog down. When the throttle is low or set the idle I can't keep it running. I assume the fuel pump upgrade was done correctly since I can get it to run open. Not sure what I am missing.

Its your engine do what you want. Dont check the timing and keep fighting it if you want i`m done here.

Timing controls spark, In troubleshooting of outboard engines, We start with#1 compression testing#2 open air gap spark testing#3 fuel diagnostics WE don't waver from these procedures,this is the way the book was written

Thanks for the explanation. I am new to this game. Apologies if I upset anyone with my questions.

Already told you your problem is likely a broken shock absorber spring so don't look for complications that aren't there.Regarding your problem with the single line conversion,the pulse line from the manifold needs to be as short as possible.I don't know where you mounted your new fuel pump but I mounted mine to the front portside leg of the recoil starter with cable ties and that cured it.If the line is too long it can't generate enough vacuum to work the pump.

But the pump works off a positive pressure pulse and just a slight negatve pulse.-----Slight negative pulse due to the fact that the crankcase reeds open up.

I check the contact gaps this weekend and adjusted them. I took lower unit off to look into the drive shaft shock absorber spring but I didn't pull it apart just yet as I am a little hesitant to tear into that section. It did look like the drive shaft bushing may be bad because it looked like there was bad lower casing fluid oozing up into the impeller housing. I still need to run it without the recoil starter and no lower end to see if it runs easier. If so I can start working backwards on where my problem is.

Makes no difference,if the volume in the line is too great the pulse will be too weak either way.

Well solved one problem. The hard to pull start was definitely the recoil starter. Rope started it last night and it was easy and smooth. I had the lower unit off so only ran for short bursts. Going to try and rig up some water flow without the lower to see if I can get it to idle. If so I will have confirmation that the lower needs to be torn down or replaced. I may change up the fuel lines as well. When I did the switch over the fuel line I got was very thick and take up a bunch of room.

Quick question on Timing. I have adjusted the points to 0.020 but wanted to check the timing with the fly wheel on. I don't have a timing light but have watched a few videos on how to do it with the two marks on the magneto plate and the marks on the flywheel (my fly wheel marks are almost nonexistent but there are corresponding marks where the rope raps around (at least I think so)). So when you do the timing where do you have the throttle? the magneto plate moves with the throttle and I looked at it in idle condition but that didn't seem right.

Throttle position does not matter when setting points using the timing marks.-----It just does not.

Anybody know what the overall length of that clutch is before it breaks ??

I have a 1955 Johnson CD 12 that ran fine last time i started it. It has a tendency to kick out of gear when running under a heavy load at high rpm. I was told the clutch dog is worn causing this. Does anyone know where I can get this part and how much trouble it is to change it? I have had it many years and I hate to not have it in good shape, although i do not use it anymore.