timmaybrooks
Cadet
- Joined
- Aug 14, 2010
- Messages
- 6
I have a 2000 200hp yammy ox66 efi. started with bad idling (sputtering and turning off), and running rich with a load (bogging down almost completely). Fuel starvation for sure. here's what I had done before i took it to a mechanic:
1. New pickup in the gas tank
2. new fuel lines
3. new water fuel seperator
4. new inline filter (the one with the ring that floats when there is gas)
5. new vst screen
6. removed and tested o2 sensor with blow torch (within spec)
7. new lp fuel pumps
8. had injectors cleaned tested (nothing wrong with them was the report)
Time for a mechanic
9. Good compression test
10. good spark
11. Good fuel pressure test at idle only (this will be important later)
12. tps link and sync (fixes idle!!!!!)
13. replace electric fuel pump orings
14. reset and cleaned needle on float valve
15. water test reveals bad fuel pressure psi with load. gets to 35psi and starts surging at 3500rpms and loses pressure (bad electric fuel pump ad per mechanic right?)
Got boat back from mechanic to replace electric fuel pump myself...Here's where it gets interesting:
16. replace hp fuel pump with a spankin new one (includes new vst screen) and fires right up and idles perfect...but wait... bad gasket on the positive terminal causes a small fuel leak at the top of the vst before i can perform water test.
17. take vst apart again and replace gasket...no leak. fuel pump turns on fine. button vst up.
18. turn the ignition back on and can't get the dang thing to fire!! Pump still turns on, but no fire. (Thinking vapor lock at this point from vst to injectors because it JUST WORKED the day before).
19. bleed air from shrador valve...still nothing.
20. re verify we are starving fuel by squirting gas directly into throttle body. engine fires and runs fine, and shuts off immediately once the small amount of gas squirted burns. wont fire again until i squirt more gas.
21. check to see if we are getting 12 volts at the electric fuel pump. pump turns on, but only getting 11.5 volts give or take...uh oh
22. As per repair manual, check main relay (get 12 volts just fine), and 30 amp fuse (replaced with spare just in case)...still nothing
22. do another pressure test at the shrador valve. when ignition turns on and pump runs...only 20psi max (needs to be 35.6 as per manual)
23. clean pressure regulator screen at top of vst
24. another fuel pressure test...still 20 psi (now I start thinking I purchased a bad fuel pump).
25. take return hose off top of vst (above shrador valve) and bleed out any air in desperation. re connect and still get 20 psi. turn engine over and pressure completely dies.
26. repair manual says check pump resistor on front of engine cowling... its an ohms test on the volt meter. reads .8 ohms and needs to be at .53 to .57 as per manual.
27. in an effort to rule out the resistor, hook up fuel pump power directly to a car battery at 12 volts (bypassing resistor)...still get 20psi (sigh)
So here's where I am now... definitely had a scary reading on the resistor, but doesn't explain the 20psi only at the shrador as i bypassed it. i am leaning towards I bought a lemon electric fuel pump, but why would it work as soon as I replace it (fires right up and idles perfectly), then only fails once I replace the terminal's gasket?
Anything someone would be able to help with would be amazing as this is the culmination of 6 months of dead ends. All I want to do is go fishing once this year.
1. New pickup in the gas tank
2. new fuel lines
3. new water fuel seperator
4. new inline filter (the one with the ring that floats when there is gas)
5. new vst screen
6. removed and tested o2 sensor with blow torch (within spec)
7. new lp fuel pumps
8. had injectors cleaned tested (nothing wrong with them was the report)
Time for a mechanic
9. Good compression test
10. good spark
11. Good fuel pressure test at idle only (this will be important later)
12. tps link and sync (fixes idle!!!!!)
13. replace electric fuel pump orings
14. reset and cleaned needle on float valve
15. water test reveals bad fuel pressure psi with load. gets to 35psi and starts surging at 3500rpms and loses pressure (bad electric fuel pump ad per mechanic right?)
Got boat back from mechanic to replace electric fuel pump myself...Here's where it gets interesting:
16. replace hp fuel pump with a spankin new one (includes new vst screen) and fires right up and idles perfect...but wait... bad gasket on the positive terminal causes a small fuel leak at the top of the vst before i can perform water test.
17. take vst apart again and replace gasket...no leak. fuel pump turns on fine. button vst up.
18. turn the ignition back on and can't get the dang thing to fire!! Pump still turns on, but no fire. (Thinking vapor lock at this point from vst to injectors because it JUST WORKED the day before).
19. bleed air from shrador valve...still nothing.
20. re verify we are starving fuel by squirting gas directly into throttle body. engine fires and runs fine, and shuts off immediately once the small amount of gas squirted burns. wont fire again until i squirt more gas.
21. check to see if we are getting 12 volts at the electric fuel pump. pump turns on, but only getting 11.5 volts give or take...uh oh
22. As per repair manual, check main relay (get 12 volts just fine), and 30 amp fuse (replaced with spare just in case)...still nothing
22. do another pressure test at the shrador valve. when ignition turns on and pump runs...only 20psi max (needs to be 35.6 as per manual)
23. clean pressure regulator screen at top of vst
24. another fuel pressure test...still 20 psi (now I start thinking I purchased a bad fuel pump).
25. take return hose off top of vst (above shrador valve) and bleed out any air in desperation. re connect and still get 20 psi. turn engine over and pressure completely dies.
26. repair manual says check pump resistor on front of engine cowling... its an ohms test on the volt meter. reads .8 ohms and needs to be at .53 to .57 as per manual.
27. in an effort to rule out the resistor, hook up fuel pump power directly to a car battery at 12 volts (bypassing resistor)...still get 20psi (sigh)
So here's where I am now... definitely had a scary reading on the resistor, but doesn't explain the 20psi only at the shrador as i bypassed it. i am leaning towards I bought a lemon electric fuel pump, but why would it work as soon as I replace it (fires right up and idles perfectly), then only fails once I replace the terminal's gasket?
Anything someone would be able to help with would be amazing as this is the culmination of 6 months of dead ends. All I want to do is go fishing once this year.