1986 Mercury 115 hp outboard troubleshooting.

cheers731

Petty Officer 3rd Class
Joined
Jul 4, 2009
Messages
85
Hi Folks,
Help needed for trouble shooting on 2 issues after taking the boat for a full ride.
1st, after 2 hrs ride, the trim pump start failing. No trim up and trim down sounds weak. After switching around the wire at the relay/solenoid, the trimp up will work and trim down failed. Trim up still sounds weak and fluid leak near piston area was seen. Please help what's next beside a new solenoid replacement.
2nd, engine lose power after 15 min run at WOT (5300 rpm). It was a smooth ride at WOT (5300 rpm., 42 mph) for 15 min, then needs to slow down at now wake zone. After that, the boat can not reach to 5300 rpm anymore. The best is to reach to 4200 rpm. Engine still runs and idle smooth but just can not deliver fulll power.
I am planning to do cylinder compression test first but will appreciate any suggestion on what's next.
Thanks,

Frank
 

wired247

Lieutenant Commander
Joined
Oct 8, 2011
Messages
1,557
1. Rebuild the pump and cylinders and change the brushes in the motor.

2. You could be losing compression as the motor warms up. Test the compression cold and warm. Its damn near 30 years old and motors wear out.
 
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