1998 115 Johnson Intermittent RPM Loss

[Faztbullet]

Re: 1998 115 Johnson Intermittent RPM Loss

So are you saying it will not work with a fuel only pump? The fuel only pump has an inlet (from tank), and outlet (to carbs) and a crank case pulse connection. So why can't it be connected in the same way the VRO is connected to the vapor separator?

If you look at fuel flow, the VRO inlet(tank) is fed from separator and outlet(carbs) back in the separator,then exits top cover to the manifolds. Getting a nipple to stay in place in outlet would be a trick as VRO mounting holds outlet in place. Only way you might make this work is to remove separator and rig some plumbing and I dont think a single pump could supply enough.......

I'm going to replace the rubber gasket at the top of the vapor separator housing as it is flattened in a couple of places just to rule that out.

This will cause a fuel issue as will cracks/warped cover as the VRO is drawing a vacuum in fuel chamber and if top is leaking pump cannot draw fuel correctly. Another issue I have seen is the plastic dual fitting on cowling where oil/fuel lines attach cracked and when cowling flexes crack opens up and and fuel system sucks air but it will not leak under pressure (pumping bulb)

 

[midsized johnson]

Re: 1998 115 Johnson Intermittent RPM Loss

This will cause a fuel issue as will cracks/warped cover as the VRO is drawing a vacuum in fuel chamber and if top is leaking pump cannot draw fuel correctly. Another issue I have seen is the plastic dual fitting on cowling where oil/fuel lines attach cracked and when cowling flexes crack opens up and and fuel system sucks air but it will not leak under pressure (pumping bulb)

The connector at the cowling is the one thing I haven't checked! Will look into that this morning.

Yeah Bob, I figured the wires were alarm, but the outside possibility that it had something to do with fuel delivery crossed my mind! Getting the correct manual this Friday, hope that will get me a better understanding to the system.

Thanks all for the input, much appreciated!

 

[midsized johnson]

Re: 1998 115 Johnson Intermittent RPM Loss

Update:
Replaced entire fuel line including the connection at the cowling with a 3/8" hose coupling, rebuilt the VRO pump, and changed the gasket on the vapor separator dealio. Also, changed the fuel pickup in the tank. Yesterday and today motor ran like a scalded-*** ape! Don't know what fixed it, may have been as simple as putting more gas in the tank, but I really doubt that!

 

[trendsetter240]

Re: 1998 115 Johnson Intermittent RPM Loss

Update:
Replaced entire fuel line including the connection at the cowling with a 3/8" hose coupling, rebuilt the VRO pump, and changed the gasket on the vapor separator dealio. Also, changed the fuel pickup in the tank. Yesterday and today motor ran like a scalded-*** ape! Don't know what fixed it, may have been as simple as putting more gas in the tank, but I really doubt that!

Nice work! Thanks for updating.

Enjoy your motor. I love mine!

Cheers