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Trailbum
06-26-2011, 01:09 AM
New to the forums, looking at a neighbors 2005 Moomba Outback. D-drive, with the Holley 4-barrel carb....
Starts and idles fine, but whenever a load is put to the engine, as in accelerating in forward.... the engine stalls as if it ran out of gas.
When I look into the carb after a stall and work the throttle linkage, we're NOT getting the squirt of fuel into the venturi of the carb. If we let it sit a minute with the key "on", the electric fuel pump refills the float bowl and it will restart and run fine again.
This looked like a CLASSIC case of a partially plugged fuel filter, so we replaced the fuel filter between the tank and fuel pump, but the problem still persists..... and I'm out of ideas.... BTW, that fuel filter was an SOB to get to.... mounted to the rails, under the starter motor... a real PITA!!!! Is there perhaps another fuel filter that we're not aware of???
Has anyone experienced or heard of a similar problem??? And if so, what was the solution????
Thanks in advance,
Bill

maxpower220
06-26-2011, 09:53 AM
Disconnect the fuel line from the carb and rent a fuel pressure guage. Then you can determine how well the pump is working. Also, I would check the float in the carb. The engine already sets at an angle, it is greater when the bow rises on take off.

My only 2 inputs.

Mikey
06-26-2011, 06:00 PM
I have the 07 Outback and my fuel filter is hidden behind a panel in the ski locker at the very back of the boat,maybe there is a 2ndary one back there as well.

Engine Nut
06-26-2011, 08:42 PM
New to the forums, looking at a neighbors 2005 Moomba Outback. D-drive, with the Holley 4-barrel carb....
Starts and idles fine, but whenever a load is put to the engine, as in accelerating in forward.... the engine stalls as if it ran out of gas.
When I look into the carb after a stall and work the throttle linkage, we're NOT getting the squirt of fuel into the venturi of the carb. If we let it sit a minute with the key "on", the electric fuel pump refills the float bowl and it will restart and run fine again.
This looked like a CLASSIC case of a partially plugged fuel filter, so we replaced the fuel filter between the tank and fuel pump, but the problem still persists..... and I'm out of ideas.... BTW, that fuel filter was an SOB to get to.... mounted to the rails, under the starter motor... a real PITA!!!! Is there perhaps another fuel filter that we're not aware of???
Has anyone experienced or heard of a similar problem??? And if so, what was the solution????
Thanks in advance
Bill

The fuel pump should not run with the key in the on position. There is a fuel pump safety switch near the distributor that should only allow the pump to run when the engine is either cranking to try to start or running. The switch is actuated by oil pressure. This link will take you to a diagram of the fuel pump safety switch circuit.

ftp://ftp2.indmar.us/Wiring%20Diagrams/Misc%20Diagrams/Fuel%20Pump%20Safety%20Switch.pdf

rdlangston13
06-26-2011, 09:00 PM
The fuel pump should not run with the key in the on position. There is a fuel pump safety switch near the distributor that should only allow the pump to run when the engine is either cranking to try to start or running. The switch is actuated by oil pressure. This link will take you to a diagram of the fuel pump safety switch circuit.

ftp://ftp2.indmar.us/Wiring%20Diagrams/Misc%20Diagrams/Fuel%20Pump%20Safety%20Switch.pdf

it doesnt operate like a car and run for two seconds when the key is turn to the on position and then shut off if it does not receive a crank shaft position sensor movement?

Engine Nut
06-26-2011, 11:06 PM
it doesnt operate like a car and run for two seconds when the key is turn to the on position and then shut off if it does not receive a crank shaft position sensor movement?

EFI engines work like that but not carbureted engines. Carbureted engines have fuel pump safety switches like I described.

Trailbum
06-27-2011, 02:05 PM
Thank you for all of the replies!!!
I think our next course of action is to hook a DVM to the fuel pump leads and SEE if the fuel pump is getting 12 volts just before the engine stalls!!!
Thanks again!!!

rdlangston13
06-27-2011, 02:41 PM
EFI engines work like that but not carbureted engines. Carbureted engines have fuel pump safety switches like I described.

ahhhh makes sense, i am useless when it comes to carbs. whats a float bowl? lol

AaronWhitt82
06-28-2011, 03:29 AM
I'd check the float levels in the primary & secondary fuel bowls.
Maybe a stuck needle and seat?
Carb also might need a rebuild
Weak fuel pump pressure?
Loose connection on the fuel pump terminals

T100
06-28-2011, 12:11 PM
Same symptoms happened to me last summer and it was the oil pressure switch. Engine Nut and CanuckleHead helped me out on that repair, Thanks again guys! You saved my summer holidays!

phospher
06-28-2011, 01:39 PM
If you have a carb, when you hit the throttle you should see a shot of fuel for the accelerator pump. If you don't, then you likely have an issue with the accelerator pump. I just had a rebuild done on a holley 4160 4bl last summer because of the same issue. It was a torn diaphragm.

Trailbum
06-28-2011, 10:25 PM
The fuel pump should not run with the key in the on position. There is a fuel pump safety switch near the distributor that should only allow the pump to run when the engine is either cranking to try to start or running. The switch is actuated by oil pressure. This link will take you to a diagram of the fuel pump safety switch circuit.

ftp://ftp2.indmar.us/Wiring%20Diagrams/Misc%20Diagrams/Fuel%20Pump%20Safety%20Switch.pdf

Engine Nut.... Thank you SO MUCH for posting the wiring diagram and the description!!! Using this, I did some troubleshooting using a DVM with the boat on the trailer and a homemade flush kit attached to the garden hose. Here is what I found:

With the DVM on the contacts of the oil pressure switch, had 12 volts on the orange wire while cranking the starter motor (good).
With the ignition switch "on" I had 12 volts on the purple wire (good).
However, I LOST 12 volts from the orange & red when the engine was running!!!!

With the DVM connected to the red wire on the fuel pump, I had 12 volts while cranking the starter (good).... Then nothing (no voltage) after the engine started. Engine ran for about 30 seconds before it "ran out of gas."

Disconnected the red (+) wire from the fuel pump and left dangling. Ran a jumper wire from the battery directly to the (+) side of the fuel pump. Engine started and ran for as long as I wanted to run it, as the fuel pump had a constant 12 volts going to it!!! Ran absolutely perfectly!!!!
Here's where the plot thickens though..... While running the engine with the fuel pump (+) terminal jumpered directly to the battery and the red (+) fuel pump lead disconnected and just dangling, I HAD a good 12 volts on the red (+) fuel pump lead!!!! But whenever I plugged it back into the fuel pump with the engine running, it would immediately drop to ZERO voltage when plugged into the fuel pump!!!

I was sort of leaning towards a bad fuel pump, perhaps a short or something in it.... but that wouldn't explain why it works perfectly when connected directly to the battery!!!!

Is it possible that the oil pressure switch is bad??? The only time it reads 12 volts on the red (+) lead with the engine running, is when the red (+) lead is DISCONNECTED from the fuel pump... (???)

I'm thinking my next course of action is to replace the oil pressure switch and see what happens... Yes, no???? BTW, with the engine running, the oil pressure gauge on the dash showed 40+ PSI.

Is the oil pressure switch readily available from an auto parts store, or is it a "dealer only" item???? (I've never seen another one like it)... Anyone out there know what the part number might be and where I could possibly find one????

Think I covered everything... Thanks again for all the replies and help!!!

Trailbum
06-28-2011, 11:32 PM
Did some searching on Google and I believe the part I need is the "Fuel Pump Safety Switch" Indmar P/N 501013. This boat has the newer style switch with two terminals, rather than three.
Can someone verify this part number????
Thanks in advance!!!

Trailbum
06-30-2011, 01:20 PM
Picked up a "Fuel Pump Safety Switch" from a local dealer. Installed the switch and started the boat on the trailer, using the homemade flush kit.
This time, had a good steady 12 volts on the red (+) lead of the fuel pump with the engine running!!
Dropped the boat in the water and she ran like a "Raped Ape"!!!!!
Thanks again for the replies and help!!!! :)

kaneboats
06-30-2011, 01:56 PM
Well, that's certainly good to hear. Nothing like a fixed boat-- and you did it yourself.

alejofd
07-04-2011, 11:17 AM
I had the same problem on an Outback 05. It turned out to be the fuel filter, at the very back of the boat, behind the fuel tank. Replaced it and the problem disappeared.