1992 Volvo 230B SP-C trim unit troubleshooting

Fishybass

Recruit
Joined
Jun 12, 2013
Messages
3
Hi All,

I just purchased a boat with this motor after it had been sitting for three years. The drive will not move up or down when the trim button is pressed. I have worked through my entire trim system and have determined that all of the components appear to be operating normally (tested sending unit, relays, override function seems to work when the sender indicates motor is too high, hydraulic motor works when jumped from a battery at the motor). But, I don't get current at the hydraulic pump motor when the trim button in the throttle is pushed. The relays activate as they should. It reads -0.7V and +0.7V at the pump motor when the up or down trim buttons are pressed respectively. The meter in the dash reads 12+V on the battery, so there is a voltage drain somewhere. On a possibly related note, the engine won't start. I am not getting spark on the engine. The starter turns over. I thought it was a blown ignition coil because the resistances were out of spec. Can anyone think of a common cause? Otherwise is there an option besides a short? I see a 50A fuse on the positive side in the attached wiring diagram - I have not been able to locate this fuse. Any ideas on location? I checked under the dash and the drawing would indicate it is near the stern relays and pump, but I don't see it near there. Your thoughts are welcome. I'm trying to get the wiring diagram to upload, but it isn't working right now -- it just keeps processing. If I get it to work I'll post it. Thanks in advance!
 

Fishybass

Recruit
Joined
Jun 12, 2013
Messages
3
Re: 1992 Volvo 230B SP-C trim unit troubleshooting

After writing this post I figured out that it was a lack of power that was making it to the hydraulic motor. What I didnt realize is that the problem did in fact originate at the same place... the 55 Amp fuse on the engine. The fuse controlled both the ignition coil and the hydraulic pump. What I didn't realize is that the fuse is unlike any I've ever seen... a big hunk of white plastic... located on the engine near the circuit breaker. The fuse was also funny... it would test fine off of the engine, but failed on the engine -- probably due to plastic deformation. So, I believe the start of my problem came with the potentiometer falling out of adjustment... it allowed the engine to raise too high. When the motor hit the top it started drawing too much current which blew the fuse.
 
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