When running at cruise speed there is a noticeable loss of power when trimming the motor, both positive and negative…Also when running at higher rpms(>5000) the motor wants to cut out for 2-3 seconds at a time(loss of approx 200 rpms) and will come right back up to high cruise. It doesnt cough or sputter but almost acts like a rev limiter…I can cruise all day at 4500 with no problems. WOT is approx 5650…Motor runs like a top other than that. Three fuel pumps are relatively new…
Any ideas??? Voltage regulator maybe?? Any thoughts on whether the two are mutually exclusive or could one issue cause both of these symptoms?
Thanks for the help in advance…
you need a digital voltmeter connected to the motor and run the motor at speed, and operate trim, so you can see what that teh voltage is doing.
could easily be 1 issue
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How old is the battery? The OX66 does require a minimum amp hour rating of 100, 512 CCM and 182 minute reserve. Of course bigger is better
O2 sensor?
Set the trap boys, we going to pass through them again!!
my hpdi was doing the same thing, turned out to be very simple fix. Cheap fuel line with ethanol created a barrier that wouldnt allow enough fuel flow at high rpms. If you dont have and ethanol rated fuel line, get one. Looked at way too many things before I realized how simple a fix it was
bulletsrcheap
i have a 2000 200ox66 that started doing the samething this weekend… will idle all day long but will cut back at higher rpms… replace some battery cables and installed a new fuel line from tank to fuel filter… when hitting big wake it cuts back more often any ideas?? let me know if you figure out wat your problem is and ill do the same
2220 Keywest
200ox66 Yamaha
Had the same problem with my 2000 ox66 250. Ran fine until hitting a big bump, and port engine would cut back. Happened one day when it was calm, engine cut back. Put volt meter on fuel pump and was only getting 9 volts. Replaced fuel relay, and full steam ahead.
Plum Crazy
26 Regulator/250’s
THE PLUM gonna try to replace the fuel pump relay this weekend in hopes that it will fix my boat… pretty easy and resonable$$ fix? thanks
2220 Keywest
200ox66 Yamaha
Fuel relay is a expensive part for no more than it does. Its a relay pure and simple. I used a horn relay from NAPA sodered the wires, and incased it in epoxy. Spent 15 dollars instead of $238.15. The Yamaha part number is 65L-81950-01-00. The NAPA relay has a higher amperage contact rateing. Been running strong with no hickups for more than 2 years.
Thanks Plum priced one yesterday and had no idea a relay could cost that much… ill try the napa relay in hopes that will fix it and if not wont be out $240.00
2220 Keywest
200ox66 Yamaha