I will be the first to tell you that I am not a seasoned outboard technician. However, with the info I have found on this site and the amount of work I have done using my OEM Merc service manual and seloconline subscription I thought I was getting pretty good! WRONG... Recently I discovered that the #4 hole on my Inline 90 was dead. After following the manuals troubleshooting procedures etc I ended up swapping my swithboxes (about 45min to change 20 wires around) only to discover I had a dead #4 coil. Would've been nice if the manual had me check that before swapping switchboxes! So, at this point I am pretty proud of myself and feel that I saved some money and even better my boat was running great and kicking some major ***** compared to they way it was performing before.
With my motor woes behind me, yesterday I was out fishing and we were screaming down the channel wide open and all of the sudden, boom! the motor cuts out and winds down to about 2500 RPM and will pretty much only idle... I hit the throttle and no matter what I can only get to 2500 RPM and it's bogging horribly. Fuel bulb is hard etc but it's 8 MPH max back to the dock and that was it. Also, my voltage guage was pegged at 18V !
I get home and with a Walleye tournament scheduled for this Sunday I frantically go through the procedures... I have spark, I have compression, everything seems fine. I quickly decide I don't have time to waste on my amatuer skills so I call Tommy Unley (unleymarine.com) and tell him my situation. He was nice enough to get me in right away so I dropped the boat off last night and today he calls me and says he found the problem... Loose ground wires and a water leak that is getting my coils wet! Im like, are you kidding me? Loose ground wires? Luckily the water outlet at the top of the block was just a little loose so he sealed that up and tightened it.
He told me that when I had my coils apart and swapped my switchboxes I didn't tighten the ground wires well enough and that they vibrated loose. There were 3 coil grounds that were so loose he could turn the nut with his finger and on the bottom switchbox the phillips screw (lower right corner) was also completely loose and had almost fallen out.
I have read about 3 posts on here that detailed the exact same symptoms I had. Motor running great at wide open and then all of sudden nothing and the motor will only idle. Tommy explained to me that the ignition system is designed to work with a certain load on it and with my switchbox and coil grounds failing, the DC side of the system didn't have enough load on it causing the high DC voltage. Luckily I didn't cook my battery. He said I know it's aluminum but don't be afraid to get it super tight. He put blue loctite on the threads of all the failed grounds.
We took it to the ramp tonight and sure enough she ran like a dream again. No parts even had to be bought. Hopefully this helps someone. Sorry if I get a little wordy. I like details. I'll let ya know if everything holds through Sunday!
With my motor woes behind me, yesterday I was out fishing and we were screaming down the channel wide open and all of the sudden, boom! the motor cuts out and winds down to about 2500 RPM and will pretty much only idle... I hit the throttle and no matter what I can only get to 2500 RPM and it's bogging horribly. Fuel bulb is hard etc but it's 8 MPH max back to the dock and that was it. Also, my voltage guage was pegged at 18V !
I get home and with a Walleye tournament scheduled for this Sunday I frantically go through the procedures... I have spark, I have compression, everything seems fine. I quickly decide I don't have time to waste on my amatuer skills so I call Tommy Unley (unleymarine.com) and tell him my situation. He was nice enough to get me in right away so I dropped the boat off last night and today he calls me and says he found the problem... Loose ground wires and a water leak that is getting my coils wet! Im like, are you kidding me? Loose ground wires? Luckily the water outlet at the top of the block was just a little loose so he sealed that up and tightened it.
He told me that when I had my coils apart and swapped my switchboxes I didn't tighten the ground wires well enough and that they vibrated loose. There were 3 coil grounds that were so loose he could turn the nut with his finger and on the bottom switchbox the phillips screw (lower right corner) was also completely loose and had almost fallen out.
I have read about 3 posts on here that detailed the exact same symptoms I had. Motor running great at wide open and then all of sudden nothing and the motor will only idle. Tommy explained to me that the ignition system is designed to work with a certain load on it and with my switchbox and coil grounds failing, the DC side of the system didn't have enough load on it causing the high DC voltage. Luckily I didn't cook my battery. He said I know it's aluminum but don't be afraid to get it super tight. He put blue loctite on the threads of all the failed grounds.
We took it to the ramp tonight and sure enough she ran like a dream again. No parts even had to be bought. Hopefully this helps someone. Sorry if I get a little wordy. I like details. I'll let ya know if everything holds through Sunday!
