Johnson model # & shop manual

[gmarshall43]

I have a Johnson 5.5 hp motor that will start but will stall out shortly after. One cylinder has 45 psi and the other has about 20 psi. I suspect that I need to replace the rings but I would like to get a manual showing me how. Where can I get a manual and what year is this?<br /><br />Thanks,<br />Radar

 

[JB]

Re: Johnson model # & shop manual

Hey, Radar.<br /><br />Your engine could be anywhere between 30 and 75 years old. You need to find the model number on a plate attached to the mount. From that we can find the year and recommend what you do next.<br /><br />Your compression is pretty bad and one cylinder is probably toast.<br /><br />Let us know.

 

[gmarshall43]

Re: Johnson model # & shop manual

the model number is cd-15, serial number 1807693. What is normal compression for this motor and when you say toast does that mean it can't be repaired?<br /><br />Thanks for the reply<br />Radar

 

[JB]

Re: Johnson model # & shop manual

Howdy, Radar.<br /><br />Your CD-15 is a 1958.<br /><br />Your compression should be over 90psi and the difference between the two should be less than 15psi.<br /><br />Squirt a bit of WD-40 in the cylinders and redo the compression. <br /><br />If the compression improves, take your carb apart and clean out the jets and other small passages.<br /><br />Get some decarbonizing spray and give her a decarb treatment.<br /><br />Let us know what you get for results.

 

[gmarshall43]

Re: Johnson model # & shop manual

I'll give it a try and get back to you.<br /><br />Thanks

 

[gmarshall43]

Re: Johnson model # & shop manual

I tried the wd-40 with little improvement. This motor will start but will not stay running. Where can I get the decarb spray and what is my next step?