1985 Merc 50HP Tiller Gas Consumption

[I_5320]

Hey All,, I'm new to this sub-forum

Knowing Pics are preferred in Restoration Forum, I did include one below.

1985 4 cyl 50HP Merc tiller, w/power tilt. I Have not ran it yet outside of testing.

I picked up this guy last summer and planning to mount it on a converted 16.5 1985 Aluminum Sylvan side console. I'm converting to accommodate the Tiller Motor and boat was gutted when I bought. Stock the boat was about 650 lbs. I hope to keep weight under 600 lbs. Not sure if it had a gas tank under floor or up front originally.

Question is what size gas tank should I be using to run this puppy?

I did fine with a 5 gallon tank with 25hp. Many of the lakes I fish don't have fuel marinas so portability to refill is a preference. Can I get by in a day on 5 gallons with a backup at the dock? No kiddie skiing or tubing but of course usually blasting to the opposite side of the lake in the AM.

Or am I way underestimating?

 

[I_5320]

Re: 1985 Merc 50HP Tiller Gas Consumption

Perhaps I was to wordy. I'll rephrase.

Any recommendations on gas tank size for 1985 50hp Merc 2 stroke, 4 cylinder

 

[boobie]

Re: 1985 Merc 50HP Tiller Gas Consumption

An old rule of thumb. An outboard will burn 10 % of its hp rating at wot per hr. So a 50 hp mtr will burn 5 gal/hr at wot.

 

[steelespike]

Re: 1985 Merc 50HP Tiller Gas Consumption

If you stick with just cruising speed 2 6 gallon tanks should be plenty.
At the speed of your 25 it will use about 2.5 gph

 

[roscoe]

Re: 1985 Merc 50HP Tiller Gas Consumption

Depending on size of the lake....

you may be fine with 6 gallons.
Just carry a spare can the first few outings, and you will know how much gas you may need in no time.


FYI, you motor is 1980-1983.
The 1984 and 1985 Merc 50's were brown stripe like in the photo below.

 

[lakelover]

Re: 1985 Merc 50HP Tiller Gas Consumption

I have a Johnson 50 and run around on a small lake about 1.5 x 3 miles. The single six gallon tank always surprises me with how many times I can go around along the shore at a mix of cruising speed/WOT, maybe 3-4 depending on the speed. I carry a 1 gallon backup tank in case I need to get home.

 

[I_5320]

Re: 1985 Merc 50HP Tiller Gas Consumption

Thanks for the recommendations all.

On the 1985,, I had heard that also and need to research s/n more.

I had a guy at Merc repair shop tell me my s/n came up as a Canadian version and he could not look up exact year.

Made sense since spec label inside cover is in French.

 

[roscoe]

Re: 1985 Merc 50HP Tiller Gas Consumption

50 500/50 4-cyl 4576237 - 4962055 1977 USA
50 500/50 4-cyl 4962056 - 5193258 1978 USA
50 500/50 4-cyl 5193259 - 5531629 1979 USA
50 50 Classic 4-cyl 5531630 - 5531629 1980 USA
50 50 Classic 4-cyl 5531630 - 5949385 1981 USA
50 50 Classic 4-cyl 5949386 - 6275322 1982 USA
50 50 Classic 4-cyl 6275323 - 6428680 1983 USA



50 500/50 4-cyl 9136250 - 9195685 1977 Belgium
50 500/50 4-cyl 9195686 - 9248005 1978 Belgium
50 50 Classic 4-cyl 9248006 - 9420790 1979 Belgium(?)
50 50 Classic 4-cyl 9248006 - 9420790 1980 Belgium(?)
50 50 Classic 4-cyl 9248006 - 9420790 1981 Belgium(?)
50 50 Classic 4-cyl 9248006 - 9420790 1982 Belgium(?)
50 50 Classic 4-cyl 9248006 - 9420790 1983 Belgium(?)
50 50 Classic 4-cyl 9248006 - 9420790 1984 Belgium

 

[Yesterday]

Re: 1985 Merc 50HP Tiller Gas Consumption

MERCURY OUTBOARD MODEL YEAR GUIDE 40 HP (4-CYL) - 50 HP -- Mastertech Marine
Canaidan serial numbers found on this listing.

 

[I_5320]

Re: 1985 Merc 50HP Tiller Gas Consumption

MERCURY OUTBOARD MODEL YEAR GUIDE 40 HP (4-CYL) - 50 HP -- Mastertech Marine
Canaidan serial numbers found on this listing.

Thanks,, Yep,,looks like it's a 1982 sn is 7192177 it's a ELPT,,, Ontario, CA on the tag.

Only had a chance to fire it up once ,,warm up a little,, and check do a quick compression check . Once I get the boat finished I'll be digging into more on the motor.

 

[Sea Rider]

Re: 1985 Merc 50HP Tiller Gas Consumption

A 2 strokes engine consumes 10/12 % of it's HP at wot, so theoretically 5 gal/hour, in worst scenario 6 gal/hour. Your tank dimensions should be in direct proportion to what speed you want to go and for how long..

Happy Boating