1986 90hp evinrude how does the fuel pump work?

[blazerman]

I have a 1986 90hp evinrude model E90TLCDC and I am having problems that I believe are consistent with a failing fuel pump, but when I do my research I do not find a fuel pump only the VRO oil pump. The VRO on this boat has been disabled and I have been premixing for years, is the fuel pump part of the VRO? The boat wants at least half to full throttle to stay running; at slow speeds or idle speeds I have to constantly prime the fuel bulb to keep it running. Does this sound like a fuel pump issue?

 

[SparkieBoat]

yes it sounds like a fuel pump issue, the vro pump is a fuel and oil pump in one. you can get a rebuild kit for the fuel side only. since you have the oil plugged off already you could do that. you can test the fuel pump by disconnecting the fuel line where it comes OUT of the pump and pumping the bulb till you get fuel then crank the motor over, fuel should come out in fairly strong spurts, some other causes could be a cracked fuel line or a connector sucking air or something wrong with the tank pickup tube.. but those fuel pumps are a common issue for sure. google vro pump rebuild kit, I think maxrules sells it. if you think the ,it is pricey, then price a new pump.

 

[emdsapmgr]

The other option is to replace the VRO pump with an old-style premix pump. From a 125 from 1972. Part number: 438559. That pump has a 3rd hose barb for the pulse line, which will connect right up to the pulse line from your old VRO. Somewhere around $100 or so.

 

[wildwalleye]

I had a similar problem and it was the fuel pump, local small town dealer had the rebuild kit, fixed the problem, but I did find a few "loose" fuel line connectors that hadn't caused a problem YET. Sometimes on motors they have one hose that goes to 2 different size connectors and they just hope cranking the connector down will keep it tight enough. Not sure what that is all about. Isn't the VRO the WORST OMC invention of all time??? If I buy a motor and it is VRO I don't care if it does work, I disconnect it and mix the gas/oil myself. I go thru a lot of gas, so I mix it 100 gallons at a time.