Johnson qd 20 need to get up and running

bbenkaz

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I recently inherited a Johnson 10HP QD-20. It has been sitting for probably 25 or more years. It was my uncle's he said it ran when he put it away. I appears to be in good shape it has been sitting a stand out of the weather throughout its time in storage. I want to get it up and running but do not know what to expect. Should I rebuild the carb? Replace the impeller? I am also going to have to convert it to a fuel pump I found a good guide as long as it will work for my motor?

http://www.duckworksmagazine.com/05/columns/max/5/index.cfm

The bottom end has grease on the outside so I am guessing that the lower unit seals have gone bad or dryed up should I go ahead and replace these also? Here are some pictures of the motor I took. Thanks a lot to all who help.








 

Silvertip

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Re: Johnson qd 20 need to get up and running

The very first thing you need to do is to see if it will turn over. Remove the plugs and gently pull the cord. If the engine turns that's a good thing. Disassembling and cleaning the carb is also recommended as it no doubt has serious varnish and crud build-up. Befor you deal with the fuel pump, you could use a temporary gravity flow to the carb just until you are sure the engine runs. Then spend the money on the pump and impeller. Using a fresh fuel/oil mix, try and start it.
 

bbenkaz

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Re: Johnson qd 20 need to get up and running

Took the plugs out and it turns over easily. I plugged the holes with my fingers and both cyl suck and blow nicely. This seems to be a good thing. Maybe I will now check for spark. And then take the carb apart and clean it. Any hints or help?
Thanks a lot
 

F_R

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Re: Johnson qd 20 need to get up and running

I commented on the fuel pump over where you asked at aomci. They should have the pump right here at iboats. To add to what I already said:
bypasscover10hp.jpg

Sierra187351fuelpump.jpg
 

F_R

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Re: Johnson qd 20 need to get up and running

The very first thing you should do after determining that compression is ok and the motor is sound, is pull the flywheel and check the coils. It is an almost sure bet that they are bad. Those coils are notorious for cracking and it is a total waste of time and money to try to get it to run with cracked ones. They have new coils here at iboats.
crackedCoils.jpg
 

samo_ott

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Re: Johnson qd 20 need to get up and running

What a coincidence, I just got my first QD20 yesterday! I already have a QD18 and 19 but this is my first 20. 1959, the first year with the fibreglass hood. And thanks for the pics as mine is missing a few parts and now I see what 's not there. Let us know how it goes... Btw, mine is missing the pull start, does anyone know if recoil start from a 1959 5.5hp will fit as I have a spare? (not meaning to hijack your thread here but figured it kinda fit in), thx...
 

bbenkaz

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Re: Johnson qd 20 need to get up and running

How do I get this points cvr off?

It looks like there is some stuff broken off from what I think is the coils. BTW cleaned out the carb and it was suprizingly clean. The glass bowl at the bottom had some crap in it but all in all looked pretty good. I am hoping that the float is ok is seems together so I guess it will work.
Thanks a lot this forum is very helpful especially for us non mechanics like myself
 

F_R

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Re: Johnson qd 20 need to get up and running

Remove the flywheel with a tool called a vibration damper puller. It uses bolts in the 3 screw holes to pull it off. It will pull very hard till all of a sudden it will pop off. Available at auto parts stores. Buy 3 Grade 8 hardened alloy screws while you are at it, if the puller doesn't come with grade 8s

When installing new coils, have the ends of the laminations flush with the machined edges on the bosses where they mount. This will establish proper clearance to the magnets in the flywheel.

Points are gapped to .020" at widest opening.

When you reinstall the flywheel, have the shaft and flywheel tapers clean and dry and torque the nut to 40-45 ft/lbs.
 

bbenkaz

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Re: Johnson qd 20 need to get up and running

F_R said:
Remove the flywheel with a tool called a vibration damper puller. It uses bolts in the 3 screw holes to pull it off. It will pull very hard till all of a sudden it will pop off. Available at auto parts stores. Buy 3 Grade 8 hardened alloy screws while you are at it, if the puller doesn't come with grade 8s

When installing new coils, have the ends of the laminations flush with the machined edges on the bosses where they mount. This will establish proper clearance to the magnets in the flywheel.

Points are gapped to .020" at widest opening.

When you reinstall the flywheel, have the shaft and flywheel tapers clean and dry and torque the nut to 40-45 ft/lbs.

Thanks a lot ensign I will hunt up that tool and get this cover pulled off. I am going to buy a service manual once I get this thing running so I can go through it but I want to make sure that it is going to run first. Thanks for the torque specs.
 

bbenkaz

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Re: Johnson qd 20 need to get up and running

Ensign I am a little confused about the different bypass cover I am supposed to get. I searched ebay but did not find anything, but I am not exactly sure what I need. If you see one or have a part number. I am sure I am handy enough to probably modify the one I have but I am not sure what is different about it. Is it just a matter of giving the pump somewhere to mount? or are the guts different. Sorry for my ignorance and thanks for your help. I anyone sees one of these covers I need shoot me a link please, ebay or otherwise.
Thanks a lot
 

F_R

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Re: Johnson qd 20 need to get up and running

This is a different horsepower, but you'll get the idea. #71 is the cover. See the 3 bosses where the pump mounts? The part number for the 10hp version is 305751 and the #72 gasket is 301847. Gasket # 41 is 303615, comes with a Sierra pump

To modify the one you have, get a piece of aluminum, say about 3/16" thick, and cut it large enough to cover the bypass cover and be big enough for the fuel pump mounting. Drill 4 holes same pattern as the bypass cover screws, and 3 for the fuel pump. Use the pump gasket for a template. The two outer holes are to be threaded 10-24 for the pump screws, and the center one goes clear through both the adapter and bypass cover. That is where it gets the crankcase pulses to operate the pump.

The bypass cover, adapter and pump are stacked together on the powerhead. Use a second #301847 gasket between the bypass cover and the adapter.

It is best to fill the cavity in the bypass cover with JB Weld or epoxy or something, just to take up space. The reason being that extra space like that detracts a bit from the power output of the engine. Just drill the pulse hole right through it.

Hope this helps
FuelPumpMount.jpg
 

bbenkaz

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Re: Johnson qd 20 need to get up and running

Ok I think I understand the concept Ensign thanks. For now I better focus on seeing if I can get this thing to fire up then worry about that. I pulled the flywheel off today and the coils are shot. I am thinking that maybe I should just replace the coils, condersers, points, and spark plug wires. Is this well advised and if so I found a page from this forum it gave some part numbers for Napa they were for a 5.5HP but they might be the same? THe part numbers given were
Coils OMC Part Number 582995 or 584477 NAPA Part Number 18-5181

Ignition Tune-Up Kit OMC Part Number 172522 NAPA Part Number 18-5006
I think this is points and condensers

Spark Plugs Champion J6C adjust the gap of your new spark plugs to .030 inch

The spark plug wires have to be solid core right?

Please let me know if this stuff is correct I have a feeling my local Napa may not know what they are talking about I would rather go in with part numbers.
Thanks a lot.
By the way this is kinda fun I don't like mechinic work as a general rule. Woodworking is usually more fun but since I just built my whole kitchen, cabinets, drawers... I am a little burnt out. Hence the old outboard motor project, it is kinda funny looking at this thing and thinking about how it is 21 years older than I am.
 

F_R

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Re: Johnson qd 20 need to get up and running

Yeah, those are the correct NAPA / Sierra Marine part numbers. One additional one you might want is the rubber boot for the plug wires, 18-5750. You are correct, you must use "wire" wire, not the carbon string stuff used on cars. I ran across a guy recently who was still selling the clear plastic covered wires that was a fad back in the '60s. That stuff gets stiff in cold weather and you can't move the throttle. Heck, it is too stiff in warm weather too.
 

samo_ott

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Re: Johnson qd 20 need to get up and running

Just out of curiousity, why can't the original bypass cover be used and drilled and tapped for the fuel pump?

Also, I have read that one can use a Mikuna pump and connect it right to the original pulse port on the intake manifold (after removing the manifold and jamming one side of the intake) and that will work also? Which is recommended? What's the difference?
 

F_R

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Re: Johnson qd 20 need to get up and running

There is more than one way to skin a cat. Or more than one way to jury rig a cat. You could drill and tap the cover for a hose nipple to go to some other kind of pump (Mikuni). The manifold idea has been around too.

But the point is, Johnson engineered that motor for a pump many years ago and theirs is a very simple and reliable way to go and the motor would be the way it was meant to be. Why reinvent the wheel?
 

bbenkaz

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Re: Johnson qd 20 need to get up and running

How do I get the power head off of the base. I thought maybe I would remove the powerhead and clean up the inside of the motor housing as it is filthy is this a bad idea? How to remove it just loosen the 4bolts I think and pull?
Thanks oh I am still trying to locate a bypass pump cover.
Ben
 

F_R

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Re: Johnson qd 20 need to get up and running

There are 5 screws coming up from below and 3 nuts from above, under the hood. Remove the shift interlock on one side and throttle part on the other side to get at two of them. They are 1/2" wrench size.
 

bbenkaz

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Re: Johnson qd 20 need to get up and running

I got the powerhead off the nut under the bypass cvrs was a real %^&%! The inside of the water chamber is filthy and I think muddobbers were living in there. I tried to drop the lower unit I disconnected the shift rod and the lower unit bolts the lower unit dropped about 3in and hung up I did not want to break anything so I put it back there looks like something is connected inside how do I drop the lower unit all the way?
thanks
 
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