Johnson 5.5hp running on 1 pot help !!

[simonk]

Model cd21a<br />serial bi04077<br /><br />Bought the engine second hand and told all was well but when we took it out it seemed weak <br />my farther in law has looked at it and stripped it down. its only running on the top pot not the bottom. compression ok spark ok any ideas?<br />also looking for manual and where to purchase parts in the uk any help would be wonderfull<br />Thanks simon.kilburn@btopenworld.com

 

[alcan]

Re: Johnson 5.5hp running on 1 pot help !!

Remove the flywheel and inspect the mag coils. Odds are they are cracked and leaking. At times they will work fine in a dry shop invironment, when in the water the moisture in the air makes them fail right away. If they are found cracked replace them.

 

[simonk]

Re: Johnson 5.5hp running on 1 pot help !!

thanks for the info!<br />we will have a look asuming this is ok what else<br />could it be ?<br /><br />also do you know where i can source a manual and parts from ?<br /><br />thanks again for your time

 

[lark2004]

Re: Johnson 5.5hp running on 1 pot help !!

lower seal may be leaking, it seals the lower pot's crankcase. If it leaks, then the fuel air mix won't be forced up into the top of the cylinder when piston is compressing the crankcase (leaky seal=no compression)

 

[simonk]

Re: Johnson 5.5hp running on 1 pot help !!

Thankyou once again for all your help<br />at this moment my farther in law is working away and we wont be able to look at it until the weekend.<br /><br />Question <br /><br />if you turn it over and stick your thumb over the spark plug hole at its pushing air that means<br />the compression is ok ?<br />in relation to the last comment about leaky seal.<br /><br />also do you know where i can get a manual ?<br />do you know what year is is ?<br /><br />many thanks again for all you help<br /><br />Simon

 

[Paul Moir]

Re: Johnson 5.5hp running on 1 pot help !!

I belive lark2004 is refering to primary compression rather than combustion chamber compression. That is to say crankcase compression. It can be a pain in the neck to 'test'.<br />In my limited experience with leaky crank seals though, one cylinder runs lean but still produces some power - especially when the throttle's opened up. I guess the charge just doesn't have much time to leak through.<br />Go after cracked coils first - that's most often the problem by far. Often comparing how far each spark can jump will turn up the problem. Parts should be close to reasonably priced.<br /><br />Aftermarket manuals are avaliable from Iboats, various places online, and perhaps the local library. The 'Seloc' one isn't bad at all for your engine. But the original 'OEM' service tech manuals are superior, and reprints are available from the following places (US only):<br />TheOutboardWizard<br />Mastertech<br />Marine Engine<br />Ken Cook <br />It's also worth keeping your eye on ebay for these manuals, as they often go there cheap. Unfortunetly, I only see a '59 Evinrude Parts manual up there right now, which is pretty worthless without a service manual.<br />Your CD-21 is a 1964 5.5hp. Fuel oil mix is 50:1 91 or better RON Petrol to TC-W3 rated outboard oil. IE, 20ml per litre. But if it were mine, I would go a bit richer on that engine.

 

[simonk]

Re: Johnson 5.5hp running on 1 pot help !!

first of all a big thankyou for everybodys time and effort in helping me out.<br />we will when my farther in law get back look at the engine over the weekend with all of your recommendations.<br />I will keep this post updated just so we know how it was solved in the event someone else gets a similer problem<br />Once again a big thanks <br />you make the net a better place!