62 Johnson 5.5 tuneup / repair advice

[Davemattb]

My parents got my grandfathers 62 Johnson 5.5 seahorse cd-19s. My parents had it checked out 2 years ago and the mechanic said it looked and ran great. Its in almost new looking condition. It sat for 2-3 years because we didn't have a boat for it at the time. We now have a boat and I tried to get it running. It starts but doesn't want to keep running. It likes the choke a lot. It'll idle nicely for up to 30 seconds, then the engine rpms will surge and the motor will quit. I only visit for 2 weeks of the year and will be taking it in to be checked out for when I come back next month. While its in for service, are there other repairs I should have done? I'm wondering if I should have the carb and fuel pump rebuilt? Just looking for advice from people so it gets done right this time. Thanks!

 

[HighTrim]

Re: 62 Johnson 5.5 tuneup / repair advice

Welcome to iboats.

Rebuild/clean the carb. Sounds like you are running on the fuel from the bowl. Will pumping the primer bulb keep it running? What about spraying pre mixed fuel into the carb throat?

It is fairly simple. If you would like to do it yourself, we can walk you through it.

 

[Davemattb]

Re: 62 Johnson 5.5 tuneup / repair advice

It seems to run longer if I squeeze the primer. However rpms surge randomly then it quits. I am capable of doing the work but I'm leaving soon and want it running when I come back. Plus, I have a quad to fix when I get back too. I'll make sure they rebuild the carb . Any other suggestions?

 

[HighTrim]

Re: 62 Johnson 5.5 tuneup / repair advice

Hard to say for sure without being there, but an educated guess would be a faulty needle/seat or float.

 

[1946Zephyr]

Re: 62 Johnson 5.5 tuneup / repair advice

Check and make sure your fuel pump is pumping. A weak fuel pump will keep up with demand. If the line connction at the motor is bad, then it will leak air and not feed the carb properly too. You can unhook the outlet line from the fuel pump and install a longer piece of hose. Then put the end of the hose into a jar and see if it's pumping fuel into it, while it's running. If it's not, then I would say your fuel pump is bad, or you have a restriction somewhere. You could possibly have a clog, before the needle and seat also, if your fuel pumps proves out good.

 

[Davemattb]

Re: 62 Johnson 5.5 tuneup / repair advice

Thanks for advice! If I lived here i would spend the time myself but I want to enjoy my vacation . Hopefully the mechanic will be as knowledgable as you all!

 

[jmendoza]

Re: 62 Johnson 5.5 tuneup / repair advice

Remove the welch plug on the carb to expose the low speed orfices and clean them out, replace the welch plug with a new one ( carb kits availlable here at I Boats), use Threebond 1104 sealant on the new welch plug and swage it in place with a punch by flattening the top of the plug( do not over do this and collapse it!). (availlable at motorcycle shops) as Permatex Form-A-Gasket is silicon based and softens when exposed to gasoline. Silicon form-a gasket on any engine is the mark of a shadetree mechanic, OMC never used it, and neither should you.

A normal carb dissasembly, dip, and blow out with air does not usually clean out the low speed orfice pocket, so you need to remove the welch plug to do it right. Most mechanics will try and shorcut this step, or they are unaware of this issue because only these really old engines have this issue; most mechanics are too young to know about these antiques, and the trick associated with them.

 

[Davemattb]

Re: 62 Johnson 5.5 tuneup / repair advice

Mechanic said he wouldn't have time to touch it until after my next trip. Looks like I will be tackling this myself in a couple weeks when I return. I want to order some parts so let me know if I'm missing anything

First off, I wanted to order a new hose to connect the gas tank. Are these readily available or should I order from iboats? Also, what size do I need? I noticed it didn't seem to seal well, but I do not know what's normal. Wondering if that could be causing the issue I'm having?

Carb rebuild kit(. I'll make sure to blow out the low speed orifice as described above)
New float
Should I invest in a pump rebuild kit to eliminate other possible issue?
If I were to replace the gas lines, what size would I need?
I've read people recommending replacing the impeller. It was pumping water when it ran. Wasn't sure if it's necessary at this point.

Anything else you guys can think of? Luckily I have 2 mechanic friends and our neighbor is pretty knowledgable. Don't mind spending extra money if I can preserve this engine for years to come!

Thanks!

 

[OptsyEagle]

Re: 62 Johnson 5.5 tuneup / repair advice

WOW. Sounds like you are really going to throw a lot of parts, money and time at a 50 year old motor that probably only has one problem that you have just not isolated.

If it were me and I had the time, I would run it again. When it starts to die, see if squeezing the primer bulb can revive it. If it does, then it is most likely a fuel pumping problem, isolated now to your fuel pump, fuel hose, all the connections, tank vent and carb inlet valve. I would then open my gas cap to determine if it was a tank venting problem. If I had another fuel hose I would try that to eliminate that possibility and then I would determine if my fuel pump was working. To do that simply disconnect the fuel line going to the carb and pull on the starter rope. You can disconnect the spark plugs if you don't want it to start up. In any event, you should see fuel pumping out that hose. If not and you have eliminated tank venting, fuel tank hose and most connections look good, then you have a faulty fuel pump. Lastly, if squeezing the primer bulb helps revive it and fuel pumps out that disconnected fuel hose, then it almost has to be a sticky fuel inlet valve on your carb.

If pumping the primer bulb does not revive it and using the choke helps, it is probably a dirty slow speed jet on the carb or your carb needles are set too lean. That would be best dealt with by first determining that turning the needles counter-clockwise (enriching the mixture) does not help. If the carb needle changes show no change in performance then I would obtain a new carb rebuild kit and clean it well with carb cleaner or laquer thinner, blow with compressed air every oriface, and reassemble it. If I rebuilt the carb, I would probably replace the fuel hoses inside the motor as well. The alcohol resistant ones are the best and clear helps also, and they are cheap.

 

[Davemattb]

Re: 62 Johnson 5.5 tuneup / repair advice

Time is my issue. That's why I would prefer it repaired by a mechanic. I only get back 1-2 weeks per year so I'd rather have the parts handy I case I need them. I guess I'm attached to this motor since my grandpa had since new. Someday maybe I'll be able to pass it down.