I've been searching this site the last several weeks to troubleshoot issues I'm having with a craigslist special my wife decided to endeavor. I was busy at the time selling my BMW and parts via internet and she was shopping for a boat.
She found a 94 Bayliner Jazz with the Mercury sport jet 90. Previous owner claimed ignition issues and boat would run fine for a bit and then not start for awhile. The sale included new wiring harness and Mercury repair manual. I'm an engineer and work on my BMWs and Hondas, so I thought I'd give this "no test drive special" a go. Previous owner claims boat sat for 2 years with stabilized gas. I later find out previous owner purchased boat at a repo auction.
I should have known he wouldn't be able to properly diagnose this boat once he claimed the whole wiring harness needed replacement due to faulty ignition switch. I ended up hacking and swapping switches only to find other issues.
This boat was missing the ride plate and had a crack in the stator housing, likely from improper winter storage tactics. The wear ring was installed by previous idiots upside down and therefore was not getting water supply to cooling circuit. This explains previous owners "intermittent" dying issues. This motor has likely been seized who knows how many times. Cylinder compression seems fine. I think the lowest was 125 and the highest 135 psi. Sometimes it sounds a little nasty when cranking over. The high temp warning system must not be up to snuff. I understand the missing ride plate may have been from out of water starting attempts.
After dumping approx $400 to fix these issues and now that the boat is water worthy, I find crank is filled with nasty crap when cranking. After 4 recharges and 2 starter rebuilds (my father in law is very stubborn and impatient), I finally had the crank purged of the nasty crud. Most of the nasty crud was coming from the lower cylinder.
I noticed water witness lines in engine bilge, which indicates lower 1/2 of engine was submerged for up to 2 years. Dry plugs. I did evacuate old gas and replace with new Shell premium and Seafoam. Spark appeared good, although I do not have the special tool that confirms 7/16" jump.
I thouroughly cleaned carbs and noticed sticky needle valves. This explains dry plugs. Perfect. I damaged first idle tube (the rest I left alone) and replaced with hobby shop brass tubing of very similar dimensions and reinstalled with precision (same length, position and bend direction).
It was very difficult, but I finally got it started until it fell flat on it's face after 15 or 20 seconds. It did not seem to want to climb past 2k rpms or so. It took quite a bit of throttle to finally start. I may have been flooded. I've heard these engines are notorious for difficult cold starts. I noticed fuel had collected in bottom of intake horn.
I decided to recheck for spark. Now no spark. As I'm checking for spark, I notice bits of the flywheel falling out. They were pieces of magnet. Explains weak spark. I haven't torn off the flywheel yet. Is it possible this will turn into new flywheel, stator, trigger assy, etc..
I'm also concerned the fuel in the intake air horn is an indication of another issue with fuel recirc circuit. I have not searched this yet, but tripped on the comment while doing previous research.
I think I'm on the right track here but anyone with more experience, please chime in to confirm or give me other general pointers. I've wasted too much time on my 4th of July and Labor Day vacations on the lake with this boat. Anything would be most appreciated.
Much gratitude,
Treat44
She found a 94 Bayliner Jazz with the Mercury sport jet 90. Previous owner claimed ignition issues and boat would run fine for a bit and then not start for awhile. The sale included new wiring harness and Mercury repair manual. I'm an engineer and work on my BMWs and Hondas, so I thought I'd give this "no test drive special" a go. Previous owner claims boat sat for 2 years with stabilized gas. I later find out previous owner purchased boat at a repo auction.
I should have known he wouldn't be able to properly diagnose this boat once he claimed the whole wiring harness needed replacement due to faulty ignition switch. I ended up hacking and swapping switches only to find other issues.
This boat was missing the ride plate and had a crack in the stator housing, likely from improper winter storage tactics. The wear ring was installed by previous idiots upside down and therefore was not getting water supply to cooling circuit. This explains previous owners "intermittent" dying issues. This motor has likely been seized who knows how many times. Cylinder compression seems fine. I think the lowest was 125 and the highest 135 psi. Sometimes it sounds a little nasty when cranking over. The high temp warning system must not be up to snuff. I understand the missing ride plate may have been from out of water starting attempts.
After dumping approx $400 to fix these issues and now that the boat is water worthy, I find crank is filled with nasty crap when cranking. After 4 recharges and 2 starter rebuilds (my father in law is very stubborn and impatient), I finally had the crank purged of the nasty crud. Most of the nasty crud was coming from the lower cylinder.
I noticed water witness lines in engine bilge, which indicates lower 1/2 of engine was submerged for up to 2 years. Dry plugs. I did evacuate old gas and replace with new Shell premium and Seafoam. Spark appeared good, although I do not have the special tool that confirms 7/16" jump.
I thouroughly cleaned carbs and noticed sticky needle valves. This explains dry plugs. Perfect. I damaged first idle tube (the rest I left alone) and replaced with hobby shop brass tubing of very similar dimensions and reinstalled with precision (same length, position and bend direction).
It was very difficult, but I finally got it started until it fell flat on it's face after 15 or 20 seconds. It did not seem to want to climb past 2k rpms or so. It took quite a bit of throttle to finally start. I may have been flooded. I've heard these engines are notorious for difficult cold starts. I noticed fuel had collected in bottom of intake horn.
I decided to recheck for spark. Now no spark. As I'm checking for spark, I notice bits of the flywheel falling out. They were pieces of magnet. Explains weak spark. I haven't torn off the flywheel yet. Is it possible this will turn into new flywheel, stator, trigger assy, etc..
I'm also concerned the fuel in the intake air horn is an indication of another issue with fuel recirc circuit. I have not searched this yet, but tripped on the comment while doing previous research.
I think I'm on the right track here but anyone with more experience, please chime in to confirm or give me other general pointers. I've wasted too much time on my 4th of July and Labor Day vacations on the lake with this boat. Anything would be most appreciated.
Much gratitude,
Treat44