Engine Serial Number Decoded

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,063
I did some more searching around and the APWXS equates to
A=first run of engine/carb combination
P=Power Steering which obviously you have
WXS=1986 model year.
The number starting with T is the GM engine serial # T= Tonawanda Assembly Plant. This is only really important if internal engine repairs are needed since there are some differences between engines made in Tonawanda vs those made in Romulus Mi., which would have an R at the beginning of the serial number.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,063
You’re welcome!
The Cobra system is actually quite good when you learn and know the quirks of them. Mine has held up quite well in a tough saltwater environment.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,313
Any tips on the quirks?
  • get a factory manual
  • come to iBoats, search the stickies, forum and if you cant find the answer, post a thread and ask questions
  • realize you have a 35 year old boat with an obsolete drive. so parts may become expensive
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,063
Agreed get the OMC factory shop manual, they are still available. The biggest problem with the Cobras is that there were problems with the first run of shift cables that were sticky and didn’t allow the clutch dogs in the lower unit to fully engage and that caused jumping out of gear and rounded off clutch and lower unit dogs. This was corrected with a new shift cable and special tools sold by OMC to make the adjustments more accurate and less confusing. If you have any shops with an older tech who knows Cobras that can really help otherwise you may have to figure it out on your own. Most of the parts needed are out there either OEM, aftermarket or used.
So when you use the boat it should shift easily into gear and out of gear; if it’s stiff, won’t stay in gear under power or won’t go into neutral you have to get it looked at, may have to replace the shift cable. The adjustment is made up of 3 steps basically that must be followed in order. In addition there is an Electronic Shift Assist system that must be functional in order for it to be able to shift out of gear while in the water. Idle speed is important too, not more than 600 rpm in the water in gear. If you search on my user name you will see many posts on this...
The other quirk is the OMC procedure for refilling the drive with gear oil must be followed exactly.
 
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