Gas mileage
 

I have a 96 V21 with the same year 150 johnson. The boat gets very poor gas mileage. I'll go on a 10 mile day and burn 25 gallons or so. speed wise it's great out of the hole but cruises at about 22 knots at around 4300 rpm. kind of disappointing. Does this sound normal for the engine. I'm more concerned about the gas. Could It be the wrong prop maybe? any insight would be appreciated.

Re: Gas mileage
 

That year 150 was pretty thirsty, but 10 miles and 25 gallons is pretty bad unless it's a 30 foot go fast. How many hours will you run the engine to burn that much? What is your wide open RPM's?

Re: Gas mileage
 

I'm gonna say It takes me about 35 minutes to the inlet. when i get there its 3 to 4 hours of start up and shut down to set up on new drifts and to move around the area. Then another 35 minutes back. the trip is about 10 miles roundtrip plus changing positions around a local area in the bay. Just bought it last year i think it topped at about 5600 or so. not positive. I am going on memory from last season. I cruise this trip at about 4300 rpm.

Re: Gas mileage
 

Do you smell any fumes esp. when you fill up? Maybe you have a fuel leak??

Get the numbers off that prop and report back. ;)

Re: Gas mileage
 

1/2 mile to a gal!! :o

I have a 88 175 Evinrude and get like 2 1/2 to 3 miles a gal, for a ten mile trip I would use less the 5 gal!

I hate to say it but you have a leak or something some were!

Do you smell fuel at all?

Do you see oil slicks in the water around your boat?

Have you checked the foam around your gas tank for fuel?

Hows the motor run?

Do you foul plugs quick?

Something is not right in Demark!

Re: Gas mileage
 

That is poor . I have a 150hp and cruise around 27mph@35-3600rpms. I think that you have a problem somewhere . On the Wellcraft site there is a place where they posted the test results with a 150 . Try this link and look under product info and click on 1993 V21 .
http://www.wellcraft.com/

Re: Gas mileage
 

@4300 that 150 looper is burning close to 14-15 GPH. So a 35 minute run will consume roughly 8.2 gallons one way plus another 8.3 gallons the other way. Let's say conservatively you use 3-4 gallons in your start ups and shut downs while drifting, you come out to roughly 20 gallons used. Your 35 minute run one way yet ony 10 miles total for the day doesn't add up though. It wouldn't hurt to check for leaks, fuel slicks while idling. But it sounds like your off on your distance a bit. It also sounds like your propping is, my V-20 with an OLD 1.6L sea-drive cruised close to 20 @ 3800-4000.

Re: Gas mileage
 

My brother has a 1996 150 evinrude Looper on a 20ft CC . . . just like that motor and it's the biggest pig. He's got a flow scan hooked up and at 4000rpm it's burning about 14gph . . . he recently put on a new prop (17pitch viper), so the motor will rev 5300rpm range at WOT and that's made some difference. But in general that motor drinks fuel.

By comparison my 2.4L Merc gets over 3mpg at a 35mph cruise 4000rpm and I have the big venturi carbs (wh-22's with no vent jets). I don't know why those motors are so awful on fuel, but they are very reliable and well built.

I believe MJ's motor is a crossflow design which is similar to the Yamaha (what yamaha copied/stole for their nearly indestructible 2.6L motor).

Re: Gas mileage
 

:o

HOLY CARP!!!! I used to get 1 mpg in my GW 25 with twin 200 Evinrudes.......something is definately wrong.

I suggest a Johnzuki 140 to cure your gas comsumption woes. ;D

Re: Gas mileage
 

Yeah, my boat with a dud cylinder was doing better than that. Last time out we probably went 15 miles and burned 10 gallons and were on and off plane a lot. Darn 8 cylinder engines are so smooth, you don't even feel it when a cylinder drops off the line.