2003 Yamaha VX200 (OX66) Hard Start Rough Idle when warm-HELP

[Tucker]

That's right pathfinder. We need the good, the bad, the ugly...

[wlspathfinder]

Sorry for the late reply....I live in Houston and my boat is at my bay house in Rockport, and I haven't had a chance to get back down there yet. Probably next week. I am going to try the low pressure fuel pumps first along with the primer bulb. All are original and probably in need of replacement. Tucker, I will first try your test by unbolting pumps and pumping primer bulb...see if any fuel leaks through bladders. My online schematic shows I have 3 lp pumps, but it could be wrong, will find out when I pull cowling. Has to be fuel dumping somehow...just got to figure out how. 123, yamaha tech said fuel pressure held at 28 psi with engine off, so have to quiz him again (36 psi on vs. 28 psi off and holding) when I go by the shop in Edna when I head back to Rockport. He opened, cleaned, etc the VS when it was there. he found the worn needle valve, so I would think he checked the o-rings, but who knows??? I really appreciate you guys advice. I'm handy, but toubleshooting can be tricky. Will post a report when I get on it. Thanks.

[jb123]

any news?.........

[wlspathfinder]

UPDATE!! Tucker...you are the man!! Problem solved! Replaced all 3 LP fuel pumps and problem solved. 3 LP pumps on this motor. Took the old ones apart to see if I could figure out which one was leaking and one had a bulge on the bladder, but no obvious hole. When I took them off, I looked for a sign of leaking from the hole on the back, but none present. Ran on the bay for 8 hours yesterday (probably 30 warm starts plus used 20 gallons of fuel) and started perfect within a second every time. 800 rpms...perfect. Plus I caught fish!

As a side note, came back to Houston today and stopped by the dealer and talked to the owner and Tech who worked on this problem 2 weeks ago....both said they knew the test procedure and had disconnected the pumps and pumped the primer bulb to test them. No leakage was noted so they moved to the next possible cause. They figure the hole must have been small. Known them (and trust them) since I bought the boat from them 9 years ago. Owner will give me $100 credit on next repair, and was very sorry they didn't fix it when it was in.

All is good!

[Tucker]

Glad you got it pathfinder, not the man by any stretch. Pretty cool the shop owner is giving you a credit. Was this a Yamaha shop?? If so just gotta wonder...

[wlspathfinder]

yep it is.

[Tucker]

Ok just gotta ask. Isn't it a little disheartning that a bunch of hacks on a owners web site can diagnose a problem, on-line without seeing the patient engine, and methodically solve it and a pro can't?

[rodbolt17]

cause not all trained techs actually have the experience.
myself I started in the automotive world at age 15, did a 3 year vocational auto shop program at hogan high in vallejo ca, the worked various automotive dealers and shops as well as machine shops.
programmed and set up CNC lathes and mills for about six years,was an FC in the USN for 6 years and have had my own marine bussiness since 95.
I got my yamaha master tech certificate in 2006.
along the way I have been certified for honda,mercury/mariner,tohatsu,suzuki,force,volvo marine and mercrusier.
however for years most my work was actually OMC.
first thing you check ,especially on the pump eating 3.1L, is lift pumps.

[99yam40]

And I believe Rodbolt has mentioned in the past it is a good idea to replace them every few years just as preventative maintenance

[rodbolt17]

yep, its simple maint.
however a leaking fuel pump can and will blow a motor.
not only due to running lean but by the extra fuel washing off the lubrication.
kinda like "needing" a water pump.
price of that pump remains the same regaurdless of how many cylinders need boring and how much the pistons cost.
its simple maint,do it now or pay it later.