Starcraft Cheiftain Trim Problem

[A320Man]

Greetings to all. My first post here. Recently I bought a 1977 Starcraft Cheiftain 25 foot MKIV. I have been working to get it ready for a test ride. It's got the Mercruiser 888 set up. I am having a power trim problem. My boat has the Star Trim panel with 2 toggle switches and seperate activation lights. My trim pump has 2 solenoids. I have a trim sender and trim limit switches on my gimble. Does anyone know where I can get a complete electrical diagram of this system?
The only way to raise my drive is with the trim out toggle switch. The normal trim up/down toggle switch will not raise my drive. I really need a diagram to fix this problem properly. Thanks for any help you can give. JSL

 

[Grandad]

Welcome to Iboats. I'm no trim expert, but here's a manual for the Prestolite pump that may help. - Grandad
View attachment Mercruiser Prestolite Power Trim Manual.pdf

 

[smokeonthewater]

your problem is almost surely a bad trim limit switch

 

[A320Man]

Thanks for the information you guys. I am sure it will help. I really would love to see a wiring diagram of that two toggle switch Star Trim system. No telling what a previous owner did. JSL

 

[smokeonthewater]

No diagram here but the trim up and trailer switches are wired the same except that the trim up goes through the trim limit switch and tilt bypasses it.

 

[A320Man]

I did some checking today. Smoke on the water was correct. The trim limit switch is bad. It never had any continuity through it regardless of out drive position. From Full down to Full up I registered an open. I made a jumper and bypassed the trim limit switch. That didn't help either. I could not raise the drive using the normal trim toggle switch. Only using the Trailer toggle switch. I checked the normal trim switch and was surprised to find no change of outputs while toggling the trim up. My Starcraft dealer is unable to help with a replacement toggle switch. Only with the 3 round button style of trim switch. From looking online it appears Islanders also used this Star Trim panel up until 1984. After that it was on the control handle. Looks like I will try scrounging around for used stuff. Sea Choice makes a DPDT switch with a off position in the middle and momentary on with either top and bottom position. It also has 6 contacts on the back as does the original. However my original switch does not act like the sea choice schematic indicates their switch will. Possibly because my switch may be broken? I was hoping a wiring diagram would show me how it should work.

 

[smokeonthewater]

Yep dpdt momentary toggle is what you need.

 

[smokeonthewater]

No Title

This is how it should be wired.

 

[A320Man]

Thanks Smoke. I finally got some time to put a real effort into this problem. And what I found wasn't what I was expecting.
I was able to disassemble the Trim Senders. After cleaning, both gave proper readings on my Ohm Meter. But I still didn't have proper indication on my Trim Gauge.
I was checking the wires back where they come out of the Gimbal Housing into the boat. To my surprise they crumbled in my hands!
So I got a genuine Mercruiser kit. With help from my 16 year old I was able to install them without removing the drive or bell housing hinge pins. My son gently pulled the wires and split grommets into place while I manipulated the wires with a piece of hooked piano wire. Then using a Snap-On 1/4" drive swivel socket and 12" extension I was able to get the 2 bolts back into the retainer. It took about an hour of fiddling around to get everything hooked up properly. It's not a job I wish to do anytime again soon. Now all my ohm readings were correct. I adjusted the limit switch and got proper extension on my trim cylinders. However my trim gauge was still not working properly. I keep getting a reading of about 50 ohms from my gauge back to the connector for the trim sensor. I should have had almost no resistance at all. I ended up running a new wire from the gauge back to the connector and all my problems are solved. I never did have to change any dash mounted switches. A adjustment of the trim sender and all is well.
On the down side we were just notified our layoff will not be 3 months but nine. So it looks like I will end up selling the Chieftain. After 6 months of work she is ready for the water. My winter project was a new paint job. I hope the next owner will be as enthusiastic about her as I've been. Thanks Again.