need help

[akhunter83]

I just got a 1977 2 stroke 25 hp johnson, model 25R77S, which has not been started for two years and have a few questions. First whats the procedure for doing a compresion test, could i get the tester at NAPA, what do they cost? Should i change the water pump since the motor is older? What can i expect to pay for a new prop since the one that is on the motor is hammered? thanks

 

[jbjennings]

Re: need help

I'd replace the water pump. After 2 years, you may have to clean the carb. It's an easy job so I'd do it just for security. I'd also change the lower unit oil and you'll need some new drain screw washers for that. Why do you want to do a compression test? Do you suspect something or just want to know what it is? The procedure is to take all the spark plugs out, screw your gauge in and pull the motor over until you get the highest reading. Test it cold. then do the other cylinder. Hopefully you will have something over 100 lbs. and within 10% of each other. You can get them at an auto parts store for about 20 bucks but if I got 2 measurements very close to one another that was really low I'd suspect the gauge is wrong as they aren't super reliable. Mine was 20 bucks from o'reillys and I've found it reasonably accurate but I've had the check valve go out before and I'm on my 3rd one in about 10 yrs. How long has it been since someone changed the fuel lines?
A prop is probably going to run you about 80 t0 120 bucks. then again, I've heard things are higher in AK. there's a good FAQ on "awakening a sleeping outboard" in the FAQ's section that you might find helpful.
Good luck,
JBJ

 

[akhunter83]

Re: need help

Thanks for the help jb, I wanted to check the compression so i know where it was at and what to expect of the motor. I also heard people talk about testing the compression after the engine has been running whats that about? It looks like the last owner has changed the fuel lines already, so about two years ago.