How does Yamaha timing advance?

[YamaHammer]

2001 VMax VX150TL with EFI on 2002 Skeeter SX190

Son's boat. Bought it new. Said motor idled fine but on last day of BASS Elite tournament following KVD, would not put Skeeter SX190 on plane. Was in heavy rain so I thought from the beginning it was fuel related. He changed spark plugs but no difference. Idles fine but falls on its face upon acceleration.

From reading this forum, I dismantled and cleaned VST filter (was clogged) and the regular see-thru filter. No water. Ran like a champ on small lake.
Called son on out of state job. He said to take the boat to big lake and really put foot in it. Thinks the ignition was breaking down after the engine gets hot. Son has history of always believing the worst. But could it be?

If so, what besides the CDI unit could be at fault?

Presently soaking O2 sniffer in choke and carb cleaner. Sensor was pretty nasty. Will put back together and take to big lake and put foot in it in the heat of the day to see if I can get the ignition to break down, which I dont think will happen. After I hook the battery back up maybe it may store a code.

Somewhere on this forum someone spoke of timing advance rod that strips out but I cannot find the message now. How does the timing advance on this motor? Or what advances it? Crankshaft position sensor? I have found about everything else but I cannot figure out the timing advance.

After I hook battery back up and run it hard, after the weekend, maybe it will store a code. I think the VST was the problem but I will take the boat back to the dealer for testing to determine status of the engine for son's peace of mind. What all should I ask the mechanic to test for?

TPS
fuel pressure
oil pressure
Ignition output
Timing
check for codes
What else?

Thanks for this forum. Very educational.

 

[rodbolt]

Re: How does Yamaha timing advance?

on that engine timing determinates are based on several inputs, the largest is the TPS.
the ECU wont store codes on OX66. it will only display active codes.
fuel presssure tests for the low and high pressure punps can really only give good daata if done at WOT and full load.
test wheel,dyno or lake run.
there is no oil pressure on that motor.
clogged VST filter will make it fall on its face when it needs fuel.

 

[YamaHammer]

Re: How does Yamaha timing advance?

After soaking in choke and carb cleaner for two days, I put the O2 sensor back on last night and took it for test run on a small 462 acre city water supply with several fishing boats out so I only ran up and back. It ran perfectly. I did not notice surging at idle like before although the idle seems to be a bit slow.

When you trim up the motor it feels like downshifting and RPM wants to go past 5,000. I am sure the VST was the culprit but son thinks the ignition might be breaking down after it gets hot. He is working three states away and wont be back until the WalMart BFL in September. I definitely want the motor to be running perfectly in September.

I fished for a couple hours with the engine off and noticed a bit of smoke when I started the engine. The temp was in the 90's with high humidity. Could the O2 sensor be a bit coated still? But that thing ran like a scalded ape.

Could the TPS be giving too much voltage? I have checked voltage on Ford truck TPS's and worked on old stuff. This motor is the latest model stuff I have ever fiddled with. I will try to check the voltage first.

It will be next week before I can take the boat to a big lake for a long run.

Thank you rodbolt.

 

[ghind]

Re: How does Yamaha timing advance?

ox66 motors normally smoke on warm start. nothing to worry about