Topic: ’57 Golden Javelin – fuel consumption question

This topic has 30 replies, 11 voices, and was last updated 5 years, 9 months ago by outbdnut2.

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June 27, 2018 at 10:07 pm #10382
nj-boatbuilder57
Participant
Silly question, but I don’t know how else to phrase it:

Is this model engine a complete pig when it comes to fuel consumption? Seems like it doesn’t take very much "zooming around" at all to suck the needle down on the tank.

Are later (mid-late ’60s) OMC 35-40 HP engines any better? I love the look of my 57JGJ on my boat, but man…..thirsty lil’ beast! It leaves me wondering if I could be doing better with a different engine.
June 27, 2018 at 10:25 pm #78566
RICHARD A. WHITE
Participant
Lifetime Member
A piglet it is…many don’t realize that once boat is up on plane and cruising, back the throttle off to about 3/4… Your fuel consumption will decrease as will your speed, but full bore buried, it is a pig for sure…

And nice boat 🙂

http://www.richardsoutboardtools.com
classicomctools@gmail.com
June 27, 2018 at 10:27 pm #78567
nj-boatbuilder57
Participant
Thanks for the compliment! Built it myself….

Are the slightly-later designs (thinking late ’60s) of similar HP any more efficient?
June 27, 2018 at 10:37 pm #78568
RICHARD A. WHITE
Participant
Lifetime Member
I lean towards RBM’s so these big guys are not very well known to me…but I have heard the 40 hp are thirsty as well… Others should chime in…I hope..LOL

http://www.richardsoutboardtools.com
classicomctools@gmail.com
June 27, 2018 at 10:42 pm #78569
Anonymous
What does the boat and motor weight? Is the motor running in top tune, what is the compression of each cyl. ? What is the top speed of the boat and what is the engine RPM at wide open throttle? What is the dia. and pitch of the prop or what is the prop mfg. prop number? This motor should not be a gas guzzler.
June 27, 2018 at 10:49 pm #78571
nj-boatbuilder57
Participant
Last summer, before I restored this Javelin, we ran a ’69 Evinrude 25HP. Now, I realize that 25HP isn’t 35HP, but we ran for several days on a 6 gal tank…..but with this engine, a short afternoon on the lake sucks the tank to nothing.

I have a 2nd tank. Suppose I’ll just run with 2 tanks for now.

– The boat weighs about 800 lbs.
– top tune? Sure think so. All new electronics, clean carb, good gearcase, etc.
– Compression 110 top & bottom
– With me & my friend (each about 180 pounds), we’re doing about 25 MPH per my iPhone
– Don’t have a tach, so don’t know RPM…..but it’s not screaming at WOT
– Prop is a Michigan 012024 (10-1/2 x 12). Runs much better than it did with a 13-1/2" pitch prop. That was just too "tall" and bogged during acceleration.
June 27, 2018 at 11:25 pm #78574
reivertom
Participant
US Member
Think of it this way….Compared to the cost of a new motor, the gas is cheap….and you can fix a 50s OMC yourself. Mine is tough on fuel also, but I never worried about it. If I used it every day to make a living, it might be a problem , but during weekends in the summer, it’s not going to break me. Plus they just look cool. :^)
June 27, 2018 at 11:47 pm #78578
olcah
Participant
US Member
Richard and reivertom are exactly right! If the engine is running normally, backing off to 3/4 throttle or even a little lower will make a BIG difference in fuel consumption. Also suggest that you figure how many gallons you will use in a season. I found that the number is around 80-100 gallons. It would be hard to save much money on that quantity of gas. I have run 1950,s 25 and 30HP and I think you may decide that gas consumption is not really a big problem with your very nice looking motor.
June 28, 2018 at 12:09 am #78581
frankr
Participant
US Member
You ask: Are later (mid-late ’60s) OMC 35-40 HP engines any better? I love the look of my 57JGJ on my boat, but man…..thirsty lil’ beast! It leaves me wondering if I could be doing better with a different engine.

Answer: A flat "NO". No difference worth talking about.
June 28, 2018 at 12:21 am #78583
Anonymous
What is the length of your boat ? Do you have to run at full throttle to go 25mrh ? What is your minimum speed to stay on plane?
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