Fuel consumption

[TunaHead]

I know that running WOT kicks up my fuel usage. But how much compared to backing it off a bit and dropping a few MPH? Someone recently told me that running my Yamaha 150 2 stroke WOT almost doubles the fuel consumption. Range is important just now because the albacore are 30-40 miles offshore.

[THEFERMANATOR]

Not certain on your YAMMIE, but my 140 EVINRUDE looper burns around 7-9 GPH from 3600-4400(actually burns more from 3200-3600), and burns around 13-16GPH top end depending on which prop I run. These numbers are verified via a calibrated floscan guage. Most 2-stroke outboards I've run start sucking fuel above around 4200 though.

[bassarama]

I've been doing MPG averages on every trip. My top speed is 42 MPH and very seldom have an oportunity to floor it. Without a flowscan for accuracy, my best averages are at 26-28 mph cruise and I get 2.4 MPG with my 99, 150 Johnson looper.

[spareparts]

any one tried a Faria Fuel Management Gauge(simular to the flow scan), I can get a good deal on a new one, but its not a deal if they aren't any good

[TunaHead]

Most 2-stroke outboards I've run start sucking fuel above around 4200 though.

Thats the advice I'm looking for!
Thanks Ferm

[macojoe]

I do a 20 mile trip every day, with tons of moving around for new drifts and different areas.
I use 17 to 19 gal a day on my 1987 175 hp Evinrude. Doing about 25 mph as the sound is always choppy here.

[reelapeelin]

Yeah, Tuna...no doubt WOT's gonna consume MUCH more gas than lower RPMS...and it should be run there from time to time to keep it runnin' good, but in normal operation, yer gonna get best fuel economy at a reasonable speed somewhere around 3/4 throttle or a little better ... my max PRM is 6,000 and even the Honda sucks it down pretty good there, but cruisin' between 4,000 and 4,400 RPMs she do REEL nice on gas and gets around at 30 mph ;) ...

[TunaHead]

Thanks guys. Hopefully the mechanic will get the Yammie running again tonight. He thinks it's the stator that went out on the first splash last weekend. If it's ready for the weekend we'll make a tuna run on Saturday (they were 34 miles offshore yesterday). We have 2-3 or 3 other boats that'll caravan out together. The ocean is predicted to be pretty flat but I'll keep the RPM's in the suggested range and track my mileage. I'll let you know how it turns out.

[reelapeelin]

Just remember the old adage for fuel usage...1/3 out, 1/3 in, 1/3 reserve...ask yerself, "Will she do the 34 miles out on 20 gals?...well, WILL she??" ...

[randlemanboater2]

I do a 20 mile trip every day, with tons of moving around for new drifts and different areas.
I use 17 to 19 gal a day on my 1987 175 hp Evinrude. *Doing about 25 mph as the sound is always choppy here.

Last week I did 24 miles and used 5 gal. ;D

[Hammerhead]

I haven't figured it out yet but, my 165 I/O seems to get pretty good mileage.

[RobsTV]

Just upgraded from old Evinrude '75 135hp to not as old Evinrude '83 175hp ($400 deal of the decade) in my Center Console, and finished fuel tests this past weekend.

Ran out 30 miles Sunday to a few wrecks in about 70' of water. Total miles traveled were 90, and used 36 gallons, (48 gallon tank), so right at 2.5mpg. 60 miles of the trip was at cruising speed of 30mph @ 3800rpm. 6 miles was no wake river cruise, 900rpm, until we hit the gulf. The rest was slow speed looking for bottom at various time. It tops out at 43mph (GPS) at 5400rpm.

Keep in mind when comparing numbers, the hp rating change in '84/'85 means this 175hp would be about the same as an '85 and newer 150hp.

[Blue_Runner]

Rob great report and I think you hit it dead on the head when you say this:
Keep in mind when comparing numbers, the hp rating change in '84/'85 means this 175hp would be about the same as an '85 and newer 150hp.
I have a 2004 Yamaha 150 2 stroke and my numbers are EXACTLY the same as yours (if not just a tad worse ::)) .

Ya'll catch any fish?

[jasoncooperpcola]

With a 1983 Johnson 150 VRO we burn 1 MPG :o

[macojoe]

OUCH!!!

[Pipe_Dream]

When I bought my Yammi the dealer told me it was efficient, but I figured it was a sales pitch. *Most of our usage is pretty light duty, just me and one other going fishing close by, or me and the wifey cruising and drifting, so I never wanted to brag about how thrifty our engine was. *But recently we had some guests, and did a lot of fishing & cruising with as many as 7 aboard, and a lot of water skiing and tubing with a full boat, too. *I filled the tank before they came, and again after they left. *Here's the skinny:
38 gallons of fuel consumed in 8 hours running time, which comes out to 4.75 gph. *I think that's pretty good. * :)

[phatdaddy]

4.75 x $3.00 (gas & oil)=$14.75 dollars per hour or .25 cents a minute.

good cheap fun..............

[Pipe_Dream]

good cheap fun..............
Well . . . I suppose if one doesn't include purchase, insurance, maintenance, and slip fee in the equation . . . then yeah, it's cheap fun! ;)

[phatdaddy]

i also forgot fried chicken & lipton green tea, oh well

[Pipe_Dream]

That would be SWEET tea, and tater salad. :D

[hangbelly]

randleman what engine you runnin to get milage like that? and what happened to your stars and posts? I thought you were all fixed up.?

[randlemanboater]

I have a 2003 Johnson 140 4 stroke (same as a Suzuki).

I am fixed.........well, my profile is fixed.

[hangbelly]

Thats very impressive fuel mileage. Are the Johnsons the same dough as the Suzuki's? I havent seen anyone with a Johnson out here but I am starting to see a few more of the suzukis. I hear they get up and move better than most and they are high maitenence. Any truth to those rumors?

[randlemanboater]

I have run mine for 4 seasons now, I have changed the oil 3 times.

This winter I will probably put in a new waterpump just because.

I pull skiers w/ no problem, top speed is 39-40.

As for price, I haven't looked lately, 4 years ago mine was 9K for everything, motor, controls, prop, monitoring unit (idiot lights), wiring harness, tax.

I have been very pleased with mine.

[Hammerhead]

Finally figured out I get about 6 miles a gallon @ 3100 rpms....or about 26 knts.

[tsubaki]

Slowly narrowing the bugs in the boat, now I'm concentrating on the engines performance while in water.
Right now I need to clean (or rebuild) the carbs and check timing cause it's running way rich, to the point of fouling the plugs.
Photo of fuel consumption at 31mph and rpm. *:-[http://i175.photobucket.com/albums/w159/tsubaki3/Picture282.jpg
New plugs with 30 minutes run time on them (after being wiped off with a wrag).
http://i175.photobucket.com/albums/w159/tsubaki3/Picture286.jpg
It will quickly do 41mph at 5000rpm (and draw 22.5gph).
I was expecting about 8gph at 30mph.
We'll see when done with the adjustments if it improves. :-/
By the way this wasn't at best trim, speed, etc, etc.
We were just trying the motor's reaction to various circumstances. I'm sure the numbers would have been a little better by picking the best operating range (which was what I was trying to do till it started fouling the plugs).

[Airslot]

Differnt critter all together, but for refernece, my 88 Merc 150 burns a little under 8 ghp at 4k getting 28-29 mph.

'Slot

[tsubaki]

I'm sure (hoping) these numbers are way out of wack but felt they needed posting in case someone seen or knew something I didn't.

[phatdaddy]

if your burning 13.2 gph & doing 31 mph, that's approx 2.3 mpg right. my 95 150 mariner gets 2.3-3.0 depending of load & seas. i don't have a fuel gauge, i just fill up & set the odometer on the gps. if i go 70 miles, it always takes 30 -35 gallons to top it off.

[THEFERMANATOR]

Hey tsubaki, those fuel burn numbers aint all that bad for a cross-flow JOHNNY-RUDE. Clean your carbs and try running some standard style plugs in her, those surface gap plugs are for extended high RPM usage. They are notorius for fowling at low RPM's for no apparent reason.

And if you want to talk about a fuel hog, I can bring my flats boat with the XRI MERC into the discussion. All I'll say is she LIKES FUEL!!!! But god will she jump on plane in a hurry and run shallow ;D.

[tsubaki]

That is what I found out about those type plugs in the past.
That is what the book suggested and they were a pain to find here in town.
I'll cross reference the other type and put them in.
I think I had L77JC4 plugs in during the last run, they performed about the same.
Got two carb kits yesterday and the other should be in town Thursday.
Not knowing any real history of the motor rebuilding the carbs will at least give me some piece of mind.
All the coils, wires and one powerpack appear new. The best indication I get out of this motor is it had some problem and they did several things to it to try and improve it.
The thermostat covers have been removed and resealed. One temp sensor had been cut and respliced but not removed, come to find out it was defective. I have all ideas the thermostats are missing. That will be my next venture cause the engine isn't getting much past luke warm.
One more step at a time. :-/

[THEFERMANATOR]

If you don't have T-stat's, it will always foul plugs at slow speed's. Been there, done that. T-stats are vital to keeping these engines from fouling. Most people overlook them. Also do the bypass valves and springs while your there.

[tsubaki]

Thanks Theferm, at least I got some ideas now of the possible problems. To top things off I never checked the plug gaps on the L77JC4 plugs, come to find out they were between 25-32 instead of 40 like recommended.
Cleaned and replaced floats and valves in two of the carbs yesterday and found no real contaminations.
Had water lines on two of the floats but no evidence of varnish.
Waiting on the last carb kit.
Might remove the t-stat covers today.

[bigshrimpin]

http://i175.photobucket.com/albums/w159/tsubaki3/Picture286.jpg

Yikes that motor is running rich. Paper bag brown is the color you want.

[tsubaki]

Removed the thermostat covers and they are in there.
Going to replace them (& bypass)when they show up.
Also going to run the L77JC4's when I reassemble what I've removed to do this.
Any ideas of all the fouling or running rich? Anybody?
The two "cleanest" ones came from the two top cylinders, the rest were about the same.

[THEFERMANATOR]

What does your airbox look like? Is it gummed up inside? You may also want to change out your recirc valves while your in there.

[tsubaki]

The intake (flame arrestor) is damp, oily (but not gummed) like most I've seen. Easy to wipe off.
And the recirculating valves? If it's the ones in the thermostate covers, yes planning on changing them.

[THEFERMANATOR]

The valves I'm refferring to are the ones that screw in by the carbs and attatch to hoses that run back and hook in by the cylinders. They are mostly for slow speed operation, but it may help.

http://www.powerheadkit.com/images/DSCN0808.JPG

[tsubaki]

I'll look at those before I put the carbs back on.
If you hadn't suggested it I wouldn't have fooled with them.
Thanks
http://i175.photobucket.com/albums/w159/tsubaki3/Picture295.jpg
And 4 more below them, not to meantion the feeder.

[tsubaki]

My mistake, they's 8 total plus the one going to the air damper (intake, breather, airbox, flame arrestor).
2 sets of 4 each are connected together and 1 to the airdamper.
The one into the airdamper was clogged and one to the set of 4 to the upper bodies was clogged.
BACK ORDERED is the last carb kit. Probably Monday.

[THEFERMANATOR]

Those check valves being plugged will definately foul plugs at low RPM's. They are a common problem that is normally overlooked.

[tsubaki]

Got the carbs rebuilt (well, floats,needles, etc.) and reinstalled them.
http://i175.photobucket.com/albums/w159/tsubaki3/Picture305.jpg
Replaced the temp sensors and t-stat, the odd part is the difference between the new and old thermostats.
http://i175.photobucket.com/albums/w159/tsubaki3/Picture303.jpg
The new ones had no flow thru or bypass where the old ones were easy to permit cooler water to run right by them.
http://i175.photobucket.com/albums/w159/tsubaki3/Picture304.jpg
Gonna try it out in the AM and see if I can adjust the idle and timing in the water.
Oh and coating the 48 (no exaggeration) bolts with antiseize was as much fun as removing cactus needles.
http://i175.photobucket.com/albums/w159/tsubaki3/Picture301.jpg
Some leftover photo's.
http://i175.photobucket.com/albums/w159/tsubaki3/Picture302.jpg
http://i175.photobucket.com/albums/w159/tsubaki3/Picture298.jpg

[tsubaki]

Summary; after replacing the plugs, thermostats, temperature sensors, cleaning the carbs and replacing the floats, needles and seats, I think I finally got the boat useable. It idles great, throttles up immediately and does everything you would expect an engine to do.
These numbers are still not perfect because we didn’t have time or decent weather to perform good tests. 20 knot winds with 30kt gusts and 8" chop.*These are short distance speeds (just enough to get leveled out).
Got a 14 x 19 ss prop at, 5000rpm-42mph-19.5gph, 3800rpm-30mph-10.5gph,1250rpm-5mph-2.5gph. Boat was ¾ full of fuel.
Next time it hits the water there are to be fishing poles in it.

[phester]

T, those #'s sound good. I rebuilt my carbs last year and it made a noticeable difference. I thought it ran well before the rebuild, but the idle wasn't perfect, and it did have an occasional misfire at trolling speed. After the rebuild....much smoother idle, NO misfire, O stall-outs. All six plugs are burning perfect. Good luck on your next outing. [BTW, 1992 150 Johnson]

[tsubaki]

Thanks, phester.
5000rpm-42mph-19.5gph (2.15mpg),
3800rpm-30mph-10.5gph (2.85mpg),
1250rpm-5mph-2.5gph (2.0mpg).
There should have been a more fuel efficient speed but didn't have time to find it.
But I'm very happy with the performance now (or till I start experimenting with another prop to raise the rpm's *;D).

[RobsTV]

Is that 5000RPM the most you can get out of it when trimmed up? If so, you are lugging the motor, (at all speeds), and shortening it's life.

You should be running WOT about 5500RPM to 6000RPM's, and if not, then looks like a prop change is needed pretty quick. I think most run a 15x17 prop with the V20 and that type motor.

[tsubaki]

5500rpm is the max for this motor.
The best trimmed up was 5200rpm back before the repairs.
I know a different prop is in the near future, most likely an aluminum 15x17.

[THEFERMANATOR]

You don't want to be taking that engine to 6000 if you want it to live very long. I know the cross-flows suffer from an RPM induced vibration at either 5700 or 6100(can't remember which right now) from the rotating mass of the engine and flywheel. Many flywheels have become 2 piece flywheels from sustained runs at that RPM. Cross-flows red-line at 5500 like tsubaki said, I would shoot for maybe another 100 RPM's. These engines pull there best down low though.