*Updates Pics* 1966 20HP Johnson Seahorse no spark

[zdurst]

Hello,

I just purchased a 1966 20HP Johnson Seahorse. Model FD-20C. I have had it running but it took a lot to get it running and it only ran for about 2 minutes and stalled about 5 times during that. I am not able to get it running anymore.

I have checked the plugs and replaced them (Champion J4C) and thats what made it run the longest. I have new gas (50:1) and new oil in the lower end. I pulled the plugs and grounded it and am not able to get a spark. There seems to be good compression.

Its not electric start. Does anyone have any suggestions on how I can get this motor running or how to get spark back?

Thanks, Zac

 

[samo_ott]

Re: 1966 20HP Johnson Seahorse no spark

Re: 1966 20HP Johnson Seahorse no spark

I just got the same engine. Have not tried to run it yet though. You should check the compression as a baseline and to eliminate it. Then you should get a spark tester and check for a good spark.

If you do not have good spark then you need to pull the flywheel. Chances are your coils are old and toast. There might be an inspection port on top to look in but if you're not getting spark you'll need to be in there anyway so pull the flywheel.

 

[zdurst]

Re: 1966 20HP Johnson Seahorse no spark

Re: 1966 20HP Johnson Seahorse no spark

Hey, thanks for the reply. I have pulled the flywheel and all I see is the nut attached to the crank. Do I have to remove this piece as well? Can you tell me what the coils look like?

Thanks, Zac

 

[zdurst]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Here is an update,

I took the flywheel off and was able to see the coils and everything. Here is a pic:

If you look at number 1 (i don't know what this part is called) but it was not making a connection. I adjusted it to make a connection. If some one could tell me what these parts are cooed that would be awesome.

After I adjusted this I put everything back together and for the fun of it I pulled it over and it started right up for about 2 seconds then died (fuel was not hooked up) Then I took it outside and put it in a bucket of water and hooked the fuel up. Pulled the choke and bang it ran so sweet. Then all of a sudden the motor jerked violently and stalled. Now it wont start again and it seems harder to pull. It did this last time. Anyone know what might be happening?

Also can someone tell me what this adjustment does?

Any info will help.

Thanks, Zac

 

[F_R]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

The breaker points (#1) need to be clean and not oily/greasy and adjusted to open .020" at their widest opening.

Jerked violently and stalled and now is tight? So what did you leave loose in there? And while I'm asking, how tight did you tighten the flywhel nut? It has to be tightened to 40-45 ft/lbs using a torque wrench. Somehow, I just know you didn't do that and it may have sheared the flywheel key. That can destroy both the flywheel and crankshaft. Do it right.

 

[zdurst]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Hey,

Thanks,

Other answers welcome as well...

Thanks, Zac

 

[Marvxyz2]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

I hope you didn't destroy that engine. It probably wouldn't hurt to take the fly wheel off and inspect for damage. If the engine is still good You probably could get instructions from faqs on this site or get instructions from a repair manual,but you need to follow the instructions carefully. I hope this helps marvxy2

 

[zdurst]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Hey,

Can someone tell me what the round piece is called that fits around the crank that the pins rub against? I had to replace the pin that holds it in place as well as the flywheel. I have cleaned everything and gapped everything to what I have been told. I have also torked the crank nut to 50 pounds. I am going to try it again tonight and see how it works.

If anyone thinks that is something that I should do before I try it let me know. Other wise thanks for everything and I will be writting more after this for more help.

Also in my second picture the is an afjustment knob for the carb I think. can anyone tell me what it would adjust becase that might be a factor in getthing my motor running.

Thanks, Zac

 

[Xcusme]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

That would be the points cam.

Adjust points: Rotate crank shaft until crankshaft key (the part you replaced) is aligned with points fiber rub block. Adjust point gap to .020. Rotate crank shaft 180 degrees , again aligning key with rub block of second point set. Adjust for .020.

Replace flywheel and torque flywheel nut to specs. The crank shaft taper and flywheel should be dry fitted, use no oil of any kind when re-assembling.


Carb Settings: FYI, The upper needle is the low speed mixture, lower needle is the high speed needle.

(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.

Setting the high and low needle valves properly:

NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle valve adjustment.

(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, wating for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.

(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustments, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

 

[zdurst]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Hey,

Thanks for the reply. I tried running the engine before reading this post but good news, the engine is now running. Well it will start and run for about 15 seconds then die. I don't think that its getting enough gas. I know that the gas is getting to the carb but the carb i'm guessing is a little dirty. I am going to take it down to the lake in the morning and try adjusting the carb like you said.

Thanks again,

Zac

 

[zdurst]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Hey,

If anyone cares, I took the carb off and dismantled it and dunked it in cleaner for about 30 minutes. Then took the air compressor to it. Re assembled it.

Now this engine runs like new. Cant wait to get it out in the water.

Thanks for everyones help.

Zac

 

[samo_ott]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

That's great. Usually a good carb cleaning will help all the old engines to run. And new coils.

 

[zdurst]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Hi, I had the boat out in the lake tonight for its first test run. It started second pull and ran really good. One thing though, its lacking power. On full throttle it should be screaming and it sounds like its at 2500rpm when im guessing it should be at like 5000 or 6000rpm.

Any suggestions? If I was to try and adjust the carb I don't know what knobs to turn. Can someone help me out or give me another reason for the lack in power.

Again its a 1966 20HP Johnson Seahorse. Model: FD-20.

Thanks, Zac

 

[Basher]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Zac

If you are trying to set your WOT (wide open throttle) then you have to set the High Speed Adjustment or lower screw. If you are trying to adjust your idle (when you are just sitting at the dock letting the motor run) then you have to set the Low Speed Adjustment or upper screw.


Basher

 

[tmcalavy]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Take it back to the lake and put the LU in the water, or put in a barrel/tub at home, with water well up the leg. Turn the lower needle/knob clockwise gently until it stops, don't force it...now back it out counterclockwise 3/4 of one full turn. Repeat with the top needle/knob, but back it out 1 and 1/2 turns. Start it and let it warm up, run the throttle up in N and adjust the bottom knob right or left until you find the sweet spot where it really hums at speed, then richen it a little (counterclockwise). Idle it down and do the same with the top knob, find the sweet spot and richen it a hair. Once this is done you are in the ballpark, but will have to tweak it a little out on the boat. Also make sure your carb and throttle advance plate are in synch. Set the throttle to the start position, motor not running, and look into the carb throat with a flashlight...the butterfly in the back should be closed, but just starting to open. As you advance the throttle it should open smoothly and be wide open when the throttle reaches FAST. If not, they are out of synch and you may have to adjust the cam roller to get them in synch.

 

[zdurst]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

Hey guys,

I looked on the carb and I cant find the two screws for adjustment. Maybe I am looking for something else. Can some one describe to me what they look like? On the from of my carb there are two adjustments. The top I can turn right out and it will not do anything, and the bottom I cant adjust at all, cant even move it.

When I had the boat out tonight I was messing with the motor. I had it running around the lake for about 35 minutes. Then under the fly wheel there is something that looks like a fin. When the throttle is turned it turns this. I put my finger on it and help it wide open for about 10 seconds and it did nothing. Then all of a sudden FULL POWER! Almost knocked me out of the boat. Ran like that for about 6 seconds. Then would never do it again.

Any suggestions? I think that the timing is a little off but pretty close. Think it might be that?

Thanks, Zac

 

[Xcusme]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

In your second picture, you have the carb mixture adjustment shaft circled in red. The outer bushing adjusts the top 'needle valve' (low speed mixture screw). The inner shaft controls the high speed mixture setting.

That 'fin thing' you played with is the spark advance cam. You need to verify the setting of the carb roller and the advance cam...this is the sync and link you hear about here in the help forums.

I think you're a bit in over your head here without a service manual. All of the settings and adjustments are outlined within. Iboats now sells OEM manuals (best for servicing) .
http://www.iboats.com/Johnson_Repai...ategory--**********.001020751--view_id.251023

 

[jbjennings]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

That surge you experienced for about 6 sec. sounds to me like the second cylinder kicked in. You may have bad spark on one cylinder. Of course, if you haven't gotten your carb adjusted, it's hard to say. the adjustment screws you've been told about are the things the knobs on the front of your motor turn. I'm thinking your fast jet is not adjustable on that year so that kind of reinforces my idea that you have bad spark on one cylinder because running it full throttle would already be right as far as adjustment and if your carb is clean, it should run fine wide open.
Just an idea, I've had a couple of motors that I went through the ignition on and still had a little problem getting good spark on both cylinders. It's a very common problem.
JBJ

 

[jbjennings]

Re: *Updates Pics* 1966 20HP Johnson Seahorse no spark

I just looked at the pic of the front of your motor and you should have a knob on that center idle adjustment screw. You also have a fixed high speed jet that is not adjustable like I was thinking. You have to have that fixed high speed orifice in the bottom of the carb bowl really clean! But, I still suspect bad spark on one cylinder.
JBJ