1992 Merc 40hp Classic ( 4 cylinder two stroke)

[airshot]

Went to go for a ride today and found a pair of wires pinched and stripped of insulation from the power tilt/trim. The bare wires touched and shorted. Went vack home and cut back the frayed section and made new connections to check things out. The 20 amp fuse was blown under the cowl, bought some new ones and the trim works once again, but the fuse blew each time I turned over the starter. Removed the plugs to look at each piston go up and down. The motor will turn over a couple times with plugs removed, but once you stop and try to turn it over again, the fuse blows right away. this motor is in mint condituon, like new stored inside its whole life. Has always ran perfect and been well maintained. I am not an electrician, but do understand basic electricity. When the wires shorted out, did this affect the starter or should I be looking at other things ??? Thanks in advance for any help or suggestions.

 

[Zum]

Took this from another sire/person...you have probably already seen something similar

"If this power fuse blows only when you turn the key to the START position, remove the 3/8" terminal wires from the solenoid, then retry (with new fuse installed) turning the key to that START position again. If the fuse still blows, there is a short in the wire leading from the "S" terminal of the ignition switch to the 3/8" nut solenoid terminal.

If it does not blow, then either the solenoid or the starter is shorted out.

If the fuse blows simply when you turn the key to the ON position, some component or wire is shorted out that leads from (connects to) the "A" (accessory) terminal of the ignition switch. In this case, finding the problem would consist of a matter of elimination...... disconnecting items until the fuse no longer blows"

 

[airshot]

Just turning to the start position does not blow the fuse, the starter must be engaged. Under compression with plugs in, the fuse blows right away. Without plugs ( no compression) it will turn over rapidly....stop and turn the key again to engage the starter and the fuse will blow. When you refer to ignition switch, are you meaning the one on the remote control box ?? Sorry for dumb questions but I am a toolmaker not an electrician.

 

[airshot]

Tried again this morning, first thing I tried was to disconnect the trim motor and see if the fuse would blow from cranking the engine. Cranked numerous times, stop, start repeat...no blown fuse !! Tried the trim only with no engine cranking, worked great from engine and remote position. Wiggled the controls, pushed, pulled to see ifbit would act up....everything perfect, so here we go trying to start with trim connected.....worked great !!!! Very happy but no clue as to what I did !!! Must be the second shift gremlins came in to solve the problem. Will be doing some driveway testing before heading back to the lake. Also made sure new section of wires will not get hooked up in the tilt area again.....whew !!!

 

[Zum]

Wonder if you still have a bare wire somewhere, maybe it got moved when you dissconnected the trim.
I imagine you already looked but never know.

 

[airshot]

Wonder if you still have a bare wire somewhere, maybe it got moved when you dissconnected the trim.
I imagine you already looked but never know.

Thanks for responding, but it was the trim wires that were pinched and stripped bare that caused the issue, the fact that the fuse was blowing when I engaged the starter was the problem. Even after I removed the bad portion of the trim wires and replaced them, I still had the fuse issue. No electrician here....but I do recall our shop electrician talking about sticking relays causing issues. There are two relays that operate the up and down trim, were they stuck ?? After sitting all night and disconnecting all power, then reconnecting the battery, everything is working as it should!! Took all the covers off and did a thorough inspection for any type of burn mark, melted wires, discoloration etc....everything look just like new and all connections tight !! Just wish I knew what really fixed it !!

 

[Still Afloat]

Airshot - I had something similar on a boat that I bought a couple of years ago. It‘s 1997 Crestliner and 115 Evenrude. Anyway, the previous owner shorted the remote tilt/trim switch at the bow. I was having intermittent issues and a blown fuse. The problem was several wires in the power head had melted the insulation off. It was tucked in there pretty good it took some digging to find the wires. The repair involved cutting one end of each wire, sliding a length of heat shrink over the area, soldering a splice and shrinking the tube over each wire.

I would have preferred to replace that portion of the wiring harness but, that was a bigger job than I wanted to dig into on an older outboard with limited parts availability.

I suspect that your outboard still has some shorted or damaged wires.

 

[airshot]

I won't say there isn't, but I have spent two days digging thru and under every cover and hiding place without any sign. No discoloration, no messed up coveringings, no nothing !! Used my super bright little micro lite to look deep down into the nooks and crannies. When I say looks like new, it is...everything is clean, shiny, literally looks like it is sitting on a showroom floor !! What happened may have been my own fault, way back when I bought it, I added a zip tie to hold these trim wires out of the way, but..thru raising and lowering the engine, the pull on these allowed the zip tie to scrape the covering off these wires in an area that was not noticible until it was to late !! The bare wires touched and the trim motor just made funny noise without moving. I discovered the issue and trued to seperate them but didn't do a very good job and the fuse blew. At home, I tried redoing the bad wires but the fuse kept blowing when I would crank the starter. Went thru 4 fuses then after disconnecting everything then reconnecting everything it worked !!! Bad series of fuses ? Been test run at least six times, yanked, pulled, wiggled everything and all works well. No sign of any bad wires that are visable and I have dug deep !!! Keeping my fingers crossed !!