1976 Evinrude 9.9

[cpdupont68]

I am working on a 1976 Evinrude 9.9. It ran fine when I put it away for winter. Now...It will run great but only if I pump the fuel bulb every couple minutes, but dies if I do not. I rebuilt the carb over the winter and again after I noticed the issue. I also rebuilt the fuel pump twice (w/OEM parts) I verify it was assembled correctly and blow test was good. The small pulse opening behind the fuel pump is clear. I installed new fuel lines and a new primer bulb. I also replaced all the hose clamps and the Evinrude fitting that connects to the engine. No Luck! Should I just get a new OEM fuel pump? I don't have access to a working one to test.

 

[jimmbo]

Welcome to iboats
You say you replaced the Fuel Lines. Did that include the Hoses between the Connector on the Motor to the Pump, and from the Pump to the Carb?
The Port on the Block you referred to as "Small Pulse Opening", is clear?
Is the Gasket between it and the Pump sealing?

 

[racerone]

I would never buy a new pump.----They are so simple to repair.----Checked for PRESSURE pulses from the crankcase that drive the pump?----Any small creatures build a nest under the cover over the winter?---Checked pick-up tube inside your tank?

 

[Crosbyman]

the engine needs fuel..and when you are supplying it manually it runs so one assumes hoses are ok, few items to check...

• make certain tank venting is ok
• disconnect carb inlet fuel hose and crank the engine to confirm fuel spits out the hose to confirm the pump is or is not ok sucking fuel out of the tank to feed the carb
• make certain pump gasket hole aligns with the pump rear pulse port and PH pulse port ....needed to run the pump.
• those fuel pumps are tricky critters to reassemble... ok after a few but tricky

Rebuilding the OMC Fuel Pump

 

[cpdupont68]

Welcome to iboats
You say you replaced the Fuel Lines. Did that include the Hoses between the Connector on the Motor to the Pump, and from the Pump to the Carb?
The Port on the Block you referred to as "Small Pulse Opening", is clear?
Is the Gasket between it and the Pump sealing?

Yes, those lines are new. I used a pipe cleaner and it appears to be clear. How can I tell if it is sealing correctly? Do I need to use Peratex liquid gasket?

 

[cpdupont68]

I would never buy a new pump.----They are so simple to repair.----Checked for PRESSURE pulses from the crankcase that drive the pump?----Any small creatures build a nest under the cover over the winter?---Checked pick-up tube inside your tank?

Check pressure with my hand as I pull the rope? I did not check pick-up. I have the original evinrude tank, does that thread out? Sorry... I am a newbie to this.

 

[cpdupont68]

the engine needs fuel..and when you are supplying it manually it runs so one assumes hoses are ok, few items to check...

• make certain tank venting is ok
• disconnect carb inlet fuel hose and crank the engine to confirm fuel spits out the hose to confirm the pump is or is not ok sucking fuel out of the tank to feed the carb
• make certain pump gasket hole aligns with the pump rear pulse port and PH pulse port ....needed to run the pump.
• those fuel pumps are tricky critters to reassemble... ok after a few but tricky

Rebuilding the OMC Fuel Pump

Tank is venting well. Carb hose is spitting fuel. The pulse port look aligned from what I can see.

 

[Crosbyman]

does it die idling or at wot.... remove the pump confirm that you feel a good pulse out of the pulse port .. if you do them recheck your pump reassembly

if it only dies idling recheck carb low speed circuit and & drip chamber under top welch plug if never inspected

lift fuel supply (tank) above carb level if engine does not die from gravity fed fuel then pump is defective (if pulse port found to be pulsing ok)

 

[cpdupont68]

Check pressure with my hand as I pull the rope? I did not check pick-up. I have the original evinrude tank, does that thread out? Sorry... I am a newbie to this.

Okay, so I checked the tank intake tube. The screen looks clear. I sprayed it good with some carb cleaner, made a fresh cut in the hose, new clamp and used silicone tape before I tightened it all down.

 

[cpdupont68]

does it die idling or at wot.... remove the pump confirm that you feel a good pulse out of the pulse port .. if you do them recheck your pump reassembly

if it only dies idling recheck carb low speed circuit and & drip chamber under top welch plug if never inspected

lift fuel supply (tank) above carb level if engine does not die from gravity fed fuel then pump is defective (if pulse port found to be pulsing ok)

 

[cpdupont68]

It will die at idle and also at increased rpm. after bowl is empty (3 min). I double checked the pump assembly because I thought I must have made a mistake the first time. Looks correct according to manual and several youtube videos. I will try your gravity trick tomorrow. Thank you so much for your help!