Mercruiser trim and shift questions

[cedarlattice]

I have a 1972 searay. Ford 302. I believe it's referred to as an 888. I have never ran this boat. I have been restoring it for the last 4 years and hope to splash it this weekend.
Question #1. The out drive pump has 1 solenoid on it and there is 3 buttons on the dash. It will go down but the only way it will go up is if it is in gear and the top two buttons are pushed. Like I said this set up is new to me but I really don't think this is normal. I unplugged it and jumped the three terminals and it goes down when the correct two are crossed. It will only go up by jumping terminals if it is in gear.

Question #2
It has a console mount shifter and there seems to be a lot of travel in the throttle. I took the shifter apart and don,t see any wear and the cable itself doesn't have any slack. I'm just wondering if some travel is normal.

 

[wahlejim]

#1 Sounds like an electrical issue. With 3 buttons on the dash, typically you find a dual solenoid system. Have you checked the wiring and compared it to the diagram? You can find schematics for dual and single solenoid systems in the stickies.

#2 How much is a lot of travel? There is typically some travel, especially in older boats. Have you adjusted the shifter cable properly? As long as you can achieve WOT when you are on plane and it goes in reverse and neutral at consistent intervals, You should be ok to run on the water and fine tune everyting (shifter cable, idle adjustments, the reverse lock valve commonly found on the older trim systems). Sounds like you are almost there! Congrats on the project!

 

[Grandad]

I had a similar problem a month ago. What I found was that there is a reverse lock-out circuit that is intended to prevent trimming up while you're in reverse, which I'm guessing might allow the prop to overpower the trim pump. I found that an accumulation of dirt had forced the little micro-switch actuator to remain pressed even when not in reverse. In this picture taken years ago before changing my transom, the green arrow indicates an arm that pivots when shifting. It has a cam action that presses the micro-switch (blue arrow). It took only 10 seconds with a pocket screwdriver to clean out the offending particles where indicated by the red arrow. It took me a lot longer to find an "early" trim circuit diagram so I could troubleshoot. It is attached. Note that there are 2 pages to the attachment. I hope this helps. - Grandad

View attachment Mercruiser Early Trim Circuit Schematics.pdf

 

[cedarlattice]

Thanks for the info. I talked to some people and the travel is normal. I cleaned the crud from around the micro switch. It was dirty and thought it was the problem. Nope. I'm wondering if it's the sensor in the lower unit. I did get the new fuel pump and water pump and installed them. I should be on the water tomorrow.