1978 900 questions

[djbeek]

I acquired this motor basically for free. It's been sitting for I don't know how long. I did a compression check today. I had done 1 through 5 and got 105 psi across the board and as I was about to attempt to get the gauge connected to #6 when I realized I hadn't put any lube in the cylinders. All I had on hand was WD40. After giving each cylinder a good shot I started over at #1 and got 140 psi all the way down. Which reading would be more accurate and did I possibly hurt anything on the first 5 "dry runs"? I have multiple questions but will start with this. Thanks

 

[Chris1956]

As long as the compression is the same. or close across all cylinders, the motor is good. The exact compression number is meaningless, as gauges are often wildly inaccurate. They are usually reliable however, and therefore useful.

 

[djbeek]

Thanks for your time. When my son in law told me he had a 90 hp boat motor I could have because all the wood, i.e., the floor, stringers and transom were rotted out of the fiberglass boat it was attached to, I thought what the heck I'll check it out. When I saw it I was not impressed. I brought it home and got it up on a stand and came here to see where to start. Now that I know the compression is good I am getting way more excited about this. I have a 1976 16 ft. Fiberform runabout that this would work great on. It needs some work on the floor but the stringers and transom are good as I tore the floor out over a year ago.
My next question concerns the tilt and trim. The trim system will need work at some point but when I got the engine on the stand it was in the trim up position and after searching threads I ended up disconnecting the 2 small hydraulic lines and it went down. My question is it doesn't go all the way down to where the engine is completely vertical as there are 2 90 degree "dog ears" (?) that stop it. If you look at it from the side there are still 2 holes in the curved part of the transom clamp where there are six holes in a curved pattern. Why would it not go all the way down until it lined up with the last hole?

 

[Chris1956]

The two dog ears are the manual tilt lock. They should be attached together, but frequently rust out and jam the transom bracket. Turn them until the ears tuck against the transom bracket, on the outside, That should allow the motor to tilt all the way down.

You should have a tilt pin in one of those holes at the base of the transom bracket. I would put the trim pin in the hole closest to the transom, for now/ If you get the PTT to work, it can stay there.

I would expect your PTT to have 4 hydraulic hoses and a pump/reservoir, which mounts in the boat.