After 8 hours of flawless boating on Saturday, on Sunday my Yammie soon began surging. Finally it wouldn't even go above idle.
I changed the filter in the sight bowl and cleaned the bowl, which had only little fine dark sediment. That didn't help.
Referring to the manual, I learned it has 4 fuel pumps. Checking the medium pressure at the VST was easy. I removed the tire valve and connected a cheap oil pressure gauge via rubber hose and clamps. (I could also monitor the high pressure with a voltmeter but because I didn't have the special harness, I'd have to break through the wires insulation.I didn't want to do that unless necessary so I monitored the medium pressure first.)
The pressure dropped from about 46 psi to almost nothing whenever the motor began stumbling. I tee'd into the low pressure hoses with a vacuum/pressue gauge and it held steady at just under 5 psi regardless of stumbling.
So the problem was in the VST. I hoped it was a plugged filter not the $1000 pump. Again, the VST bowl had only little fine dark sediment. Under 30x, it looked like rust crystals and it was magnetic. I replaced that filter, reversed voltage on the pump to back out any debris, and cemented a high energy alnico magnet in the bowl to catch any new rust particles.
For some reason, the snakey VST o-ring was stretched by the time for re-assembly. That made a 60 second job take 20 minutes of fooling around to make sure it was in the groove. I'd advise buying a new one with the filters.
Runs great again. I'm posting the above because previous posts from forum members were so helpful.
Thanks,
John
I changed the filter in the sight bowl and cleaned the bowl, which had only little fine dark sediment. That didn't help.
Referring to the manual, I learned it has 4 fuel pumps. Checking the medium pressure at the VST was easy. I removed the tire valve and connected a cheap oil pressure gauge via rubber hose and clamps. (I could also monitor the high pressure with a voltmeter but because I didn't have the special harness, I'd have to break through the wires insulation.I didn't want to do that unless necessary so I monitored the medium pressure first.)
The pressure dropped from about 46 psi to almost nothing whenever the motor began stumbling. I tee'd into the low pressure hoses with a vacuum/pressue gauge and it held steady at just under 5 psi regardless of stumbling.
So the problem was in the VST. I hoped it was a plugged filter not the $1000 pump. Again, the VST bowl had only little fine dark sediment. Under 30x, it looked like rust crystals and it was magnetic. I replaced that filter, reversed voltage on the pump to back out any debris, and cemented a high energy alnico magnet in the bowl to catch any new rust particles.
For some reason, the snakey VST o-ring was stretched by the time for re-assembly. That made a 60 second job take 20 minutes of fooling around to make sure it was in the groove. I'd advise buying a new one with the filters.
Runs great again. I'm posting the above because previous posts from forum members were so helpful.
Thanks,
John