Disabling Oil Injection on 2.5L V6 Mercury
Just finished de-activating the oil injection system on my 1997 200HP Merc.
Here is a summary of what you need to do:
Constant alarm- which indicates an over temperature problem.
Pulsing alarm (what you hear when you turn the ignition on)- which indicates an oil injection problem.
I always kept an extra gallon of oil on board in case of failure, but should you find yourself off shore with an oil alarm, you can always pour oil into the fuel tank from the oil reservoir.
My motor had an oil alarm. I went through the troubleshooting procedures in the Mercury Shop Manual. When I removed the output hose from the oil pump, it was not pumping oil. I removed the oil pump and gear shaft, and found nylon shavings in the cavity the shaft goes in. I examined the nylon pump shaft gear inside the motor (on the forward side (facing front of boat) of the cavity), and the gear did not look good. To replace it, you need to pull the crank shaft out of the motor- (not going to happen).
I ordered the oil pump plug assembly. I don?t believe they are still in production, but you can still find them. There appears to be two styles: a plug cap the shape of the oil pump base that has a about a 1 inch plug (43453 1), and the same cap with a shaft that holds the gear shaft bearing in place (I believe to be 43453 T).
This is important- you have to hold the gear shaft bearing in the bottom of the cavity in place if the gear shaft is removed. If you purchase the plug without the extending shaft, you can make a long shaft plug out of a piece of plastic about the same diameter as the shaft of the gear shaft.
The parts break down calls the gear shaft a ?driven gear?. It?s item number 21, part number 14563. I used a piece of ridged gray toilet tank tubing that I found at my local hardware store. I pushed it into the gear shaft hole as far as it would go, and marked it to the outer edge of the oil pump mounting position, than cut it off at that length. I then measured the length of the pump plug (43453 1) that protrudes into the shaft cavity, and removed another section of the tube equal to the plug length. This will hold the gear shaft bearing in place. If you can find the plug with the shaft attached, even better.
The plug (43453 1) fits VERY snuggly into the shaft cavity. There is no need for an O ring. It essentially corks the cavity. The plug with the shaft has an O-ring, and may not fit into the hole as snuggly. I reused the original oil pump screws, reversing their positions, so the short one fit into the screw hole that does not have an open end (the top one). I added a flat washer and a lock washer to each screw. Use stainless.
I put bolts into the open hose ends and clamped them down with hose clamps. A smooth pin or rubber plug would have been better, but I didn?t have any. I will probably change them later. Zip tie them so they don?t flop around.
Remove the linkage (item 23, 19385 5) that connects to the oil pump actuator to the throttle linkage. It pops off the ball joint.
You can completely remove the warning module (item 3 in part breakdown, (41470A26)) or leave it in place as I did. I may one day decide to replace the nylon crank shaft gear, so I don?t want to do anything I can?t easily reverse. Disconnect all 6 wires going to the module, and cap them off, (I used heat shrink caps).
3 of the wires have quick disconnects at the module. The other 3 wires (Green, Tan/Blue, and Purple) go up and around to the other side of the motor. The Green wire goes to the switch box (item 10, 7778A12). Mine was on the number 2 cylinder post. Remove it there by removing the nut that holds the wire?s terminal lug. Replace the nut.
The Tan/Blue wire and the Purple wire go to a terminal block (item 4, 19437 2) just above the switch box. Remove both of these here, by removing and replacing their respective nuts. Cap off all wires. Zip tie them so they don?t flop around.
Your oil injection alarm is now disabled. You will no longer hear it when you turn the ignition on, but the over temp alarm still works. If you want to test this, when you removed the Tan/Blue wire from the terminal block, there was a 2[SUP]nd[/SUP] Tan/Blue wire on the terminal post. If you ground this wire by using a jumper wire connected to the engine ground (any non-painted metal surface), the alarm will sound if the ignition is turned on. This proves that your over temp alarm will still work.
FYI- the momentary alarm you currently hear when you turn the ignition on is only testing the oil injection circuit. The over temp circuit is independent of the warning module. The only connection is from the terminal block to the helm alarm horn. Any ground applied to the Tan/Blue wire going to the helm alarm horn will make it sound. The temperature sensor on the engine block will apply a ground when it senses an over temp event.
That?s it.
Just finished de-activating the oil injection system on my 1997 200HP Merc.
Here is a summary of what you need to do:
- Remove oil pump.
- Cap oil hoses (2).
- Cap oil pump cavity- with a shaft that holds bushing in bottom of cavity in place.
- Disconnect linkage.
- Disconnect warning module wiring.
- Zip tie everything in place.
- Test over temp alarm.
Constant alarm- which indicates an over temperature problem.
Pulsing alarm (what you hear when you turn the ignition on)- which indicates an oil injection problem.
I always kept an extra gallon of oil on board in case of failure, but should you find yourself off shore with an oil alarm, you can always pour oil into the fuel tank from the oil reservoir.
My motor had an oil alarm. I went through the troubleshooting procedures in the Mercury Shop Manual. When I removed the output hose from the oil pump, it was not pumping oil. I removed the oil pump and gear shaft, and found nylon shavings in the cavity the shaft goes in. I examined the nylon pump shaft gear inside the motor (on the forward side (facing front of boat) of the cavity), and the gear did not look good. To replace it, you need to pull the crank shaft out of the motor- (not going to happen).
I ordered the oil pump plug assembly. I don?t believe they are still in production, but you can still find them. There appears to be two styles: a plug cap the shape of the oil pump base that has a about a 1 inch plug (43453 1), and the same cap with a shaft that holds the gear shaft bearing in place (I believe to be 43453 T).
This is important- you have to hold the gear shaft bearing in the bottom of the cavity in place if the gear shaft is removed. If you purchase the plug without the extending shaft, you can make a long shaft plug out of a piece of plastic about the same diameter as the shaft of the gear shaft.
The parts break down calls the gear shaft a ?driven gear?. It?s item number 21, part number 14563. I used a piece of ridged gray toilet tank tubing that I found at my local hardware store. I pushed it into the gear shaft hole as far as it would go, and marked it to the outer edge of the oil pump mounting position, than cut it off at that length. I then measured the length of the pump plug (43453 1) that protrudes into the shaft cavity, and removed another section of the tube equal to the plug length. This will hold the gear shaft bearing in place. If you can find the plug with the shaft attached, even better.
The plug (43453 1) fits VERY snuggly into the shaft cavity. There is no need for an O ring. It essentially corks the cavity. The plug with the shaft has an O-ring, and may not fit into the hole as snuggly. I reused the original oil pump screws, reversing their positions, so the short one fit into the screw hole that does not have an open end (the top one). I added a flat washer and a lock washer to each screw. Use stainless.
I put bolts into the open hose ends and clamped them down with hose clamps. A smooth pin or rubber plug would have been better, but I didn?t have any. I will probably change them later. Zip tie them so they don?t flop around.
Remove the linkage (item 23, 19385 5) that connects to the oil pump actuator to the throttle linkage. It pops off the ball joint.
You can completely remove the warning module (item 3 in part breakdown, (41470A26)) or leave it in place as I did. I may one day decide to replace the nylon crank shaft gear, so I don?t want to do anything I can?t easily reverse. Disconnect all 6 wires going to the module, and cap them off, (I used heat shrink caps).
3 of the wires have quick disconnects at the module. The other 3 wires (Green, Tan/Blue, and Purple) go up and around to the other side of the motor. The Green wire goes to the switch box (item 10, 7778A12). Mine was on the number 2 cylinder post. Remove it there by removing the nut that holds the wire?s terminal lug. Replace the nut.
The Tan/Blue wire and the Purple wire go to a terminal block (item 4, 19437 2) just above the switch box. Remove both of these here, by removing and replacing their respective nuts. Cap off all wires. Zip tie them so they don?t flop around.
Your oil injection alarm is now disabled. You will no longer hear it when you turn the ignition on, but the over temp alarm still works. If you want to test this, when you removed the Tan/Blue wire from the terminal block, there was a 2[SUP]nd[/SUP] Tan/Blue wire on the terminal post. If you ground this wire by using a jumper wire connected to the engine ground (any non-painted metal surface), the alarm will sound if the ignition is turned on. This proves that your over temp alarm will still work.
FYI- the momentary alarm you currently hear when you turn the ignition on is only testing the oil injection circuit. The over temp circuit is independent of the warning module. The only connection is from the terminal block to the helm alarm horn. Any ground applied to the Tan/Blue wire going to the helm alarm horn will make it sound. The temperature sensor on the engine block will apply a ground when it senses an over temp event.
That?s it.
