1990 70hp Johnson (power tilt/trim) Anything to look for?

[ShawnQ]

I am trying to help my friend buy a boat, and although I am not the most mechanically/structurally-savvy about boats, I know 500% more then he does, and I know how to use the internet much better.<br /><br />He is looking at a Baymaster 17' Center Console, 1991 model, with a 1990 Johnson 70hp power T/T model (I believe there were only 2 70hp models in 1990, one was power tilt, one wasn't).<br /><br />Anyways, I am wondering if there are any common problems I can look for when you go to see the boat, and if there is any specific questions/items I should ask about/look for.<br /><br />Let me know if you can help. I'd like to go view the boat on Saturday, so any help before then would be appreciated.<br /><br />Thanks!<br />Shawn

 

[DJ]

Re: 1990 70hp Johnson (power tilt/trim) Anything to look for?

Shawn,<br /><br />Can't say much about the boat except look the interior over real well looking for soft spots in the floor. Also look for any funny looking drainage coming from any holes drilled in the transom for mounting things-including the engine.<br /><br />The 70 hp looper is a fine engine. Smooth, fuel efficient and powerful. Just perform the normal checks.<br /><br />1. Compression. Should be performed with the kill switch lanyard removed and the throttle wide open. Readings should be over 100 psi and with 5-10 psi of each other, on all three.<br /><br />2. Check the lower unit fluid. It should NOT be milky in appearance.<br /><br />3. Run the tilt up and down a couple of times. If it goes up and down smooth, it's OK.

 

[ShawnQ]

Re: 1990 70hp Johnson (power tilt/trim) Anything to look for?

Djohns,<br /><br />Thanks for the tips. I plan to do the compression test and the lower unit fluid check as well. Hopefully they wont mind me pulling the plugs.<br /><br />What difference does the wide open throttle make while doing a test? Just curious. I was always just told to let the engine warm up, then pull the coil wire and crank it in neutral once it is warmed up....but, that was for a car.<br /><br />Thanks!<br />Shawn

 

[DJ]

Re: 1990 70hp Johnson (power tilt/trim) Anything to look for?

Shawn,<br /><br />You can do the test warm or cold. The cold test may yield slightly lower numbers. You are really looking for consistancy between the three.<br /><br />I've always done it with the throttle open. It allows more air into the crankcase. Remember, these are two strokes with no valves. They breathe through the crankcase.<br /><br />If they won't let you do a compression test. Tell them they can keep it.<br /><br />Good luck, let us know how it goes!