I have a pair of OX66 250's. They crank well, and mostly run well untill I get offshore. I can land hard, and one of the motors will cut off or drop back to around 1800. When I try to throttle up, it will not get above 23 to 2600 RPM's. I can give it WOT and still 23 too 26. After about five to ten minutes of this, (I usually let it idle) I can throttle it up and it runs fine. I have changed filters, cleaned VST filter, cleaned O2 sensor, changed primer bulbs, and checked all wiring. PLEASE HELP!!
Announcement
Collapse
No announcement yet.
2000 OX66 250 acking up bigtime
Collapse
X
-
Could be a faulty main relay, number 34 in this diagram Yamaha Outboard Parts 2000 SX250TXRY ELECTRICAL 3 Diagram
-
diaphram problem in fuel pumps
My acted very much the same way. It would run at low RPMs. Then as I increased the power it would ramp up and suddenly drop back down on power. It was the fuel pumps on the port side of the engine, there are 3 of them. The inner diaphram eventually gets a pinhole and doesn't work properly.
They are fairly easy to fix and cost about $39 each. If they've never been replaced, you might as well go ahead and replace them. I'm betting there's at least a 50/50 chance that's it. If not, call it maintenance.
I forgot the part number but they are clearly marked on the boats.net assembly drawing. All 3 are the same.
Good Luck
carpediemguy
Comment
-
The problem was the main relay. Hooked my meter to the fuel pump, was getting 12 too 12.5 volts when engine was running fine. When it would not throttle up I was getting 8.5 too 10 volts. Instead of paying over $150 for a Yamaha relay, I used a fuel relay for a Chevy. Sodered the connections, and incased it in epoxy. Worked great! Relay was only $12.00. Replaced them on both engines, and sea tested the boat today in a 2-3 foot washing machine. The ole Regulator did great. Thanks for the help and advice.
PLUM CRAZY
26 REGULATOR
Comment
Comment