90 hp Johnson Excessive Fuel Usage

[DonaldDuck]

I have a 1993 TJ90TLETS that's getting approx. 2.5 mpg. at various speeds. That seems excessive to me.

I've rebuilt both carburetors and did the tune-u procedure.
The VRO has been disconnected. The engine idles smooth if it is trimmed up to about level. If it's not level it idles rough.

I suspect that the PLASTIC carburetor float bowls are a problem. Both float bowl flange surfaces were warped (although they didn't leak). I sanded the flange surfaces with fine sand paper on a flat surface. That corrected the uneven flange surface. But now I wonder if there are some other malfunctions caused by the warping. The jets are screwed into the bowl. Is it possible that fuel is leaking around the threads of the jets? Who knows. I'm at a loss.

I can replace the bowls and jets for about $400. I'd like to be somewhat certain that will correct the problem before spending that much.

This motor runs like a bat out of hell. It pushes the 17' Nitro 45mph +/- until it runs out of fuel (which isn't that long).

If there is anyone out there whose had this problem I'd sure love to hear from you.

Thanks

 

[Will Bark]

My 150 Johhny gets 1.5 MPG on a 20' Cajun bay boat so I think yours may be doing fine.

 

[papyson]

sounds about right to me...a 90 2 cycle at wot with the proper boat and prop will use about 9 gallons an hour ..... drop it down to 4k rpm and it will improve....I ran a 1994 90 evinrude for 16 years...

 

[DonaldDuck]

Maybe I don't have a problem. You and Will both seem to think my mileage is close. The prop is a 13 x 19. I'll keep an eye on it.

Gracious from a Gringo