Evinrude vs Mercury

[dieselcat]

I had recently bought a 1987 evinrude 88 spl to replace my 1986 mercury 75 hp.Both motors run good.Rude is just a little faster but also more hp,and uses almost double the gas.Does this sound right?Last year i took the merc from the boat dock to the hwy 40 bridge which is 23.67 miles 1 way and used 3/4 tank of gas and i got a 12-13 gal tank so i used roughly 9 gal of gas. 3/4 to WOT most of the trip.

This year after putting the 88 rude on the boat,and went up river to newhaven which is 11.72 miles 1 way and back and used a little over a half tank,probibly about 6-7 gal of gas.Kept the rpm's at around 3500-4000 rarely ever giving it WOT.Does this seem right,for this motor to use double the gas as my 75 hp merc?

 

[tashasdaddy]

Re: Evinrude vs Mercury

all things equal on the boat, the 88 will burn more fuel than the 75. but will get you there faster. rule of thumb, 10hp = 1 gallon per hour - At wide open throttle. 88(90) hp = 9 gallons per hour, 75 hp = 7.5 gallons per hour. the 88 burnt more gas, but got you there quicker, did not take as many hours. thus it pretty much should equal out.

 

[dieselcat]

Re: Evinrude vs Mercury

Yes same boat same everything,and darn near same speed.checked with gps merc 41mph and the rude 43mph.I don't see any reason 15 more horses should burn twice the gas

 

[dieselcat]

Re: Evinrude vs Mercury

Would a link and sink procedure help out gas mileage?would it be worth getting done?this is something i would take motor to a shop to have done.

 

[56 rude]

Re: Evinrude vs Mercury

how are your wot rpm,s ?maybe your proped too high or way to low?

 

[Faztbullet]

Re: Evinrude vs Mercury

The Johnson is a 99.6 ci engine and 4 cylinders weighing 300lbs vs your old Merc that was only a 71.1 ci engine with 3 cylinders that weighed 264 lbs.
If not happy with fuel usage, reinstall the Merc on jackplate and play with props,you could get a extra 2-5 mph in fine tuning the setup.

 

[jay_merrill]

Re: Evinrude vs Mercury

I don't see the problem - you think you burned about 9 gallons with the Merc traveling 23.67 miles and you think you burned 6 - 7 gallons with the OMC traveling 23.44 miles. Sounds to me like the OMC is walking all over the Merc.

 

[56 rude]

Re: Evinrude vs Mercury

I don't see the problem - you think you burned about 9 gallons with the Merc traveling 23.67 miles and you think you burned 6 - 7 gallons with the OMC traveling 23.44 miles. Sounds to me like the OMC is walking all over the Merc.

after reading the post carefully i have to agree with you ,sounds like the rude is better on fuel to me.sounds about right as i got a fairly heavy glass boat with a 1982 rude (90) and i go 27 miles exactly on 7 gallons at a reasonable clip and top out at about 42 mph max on a good day downhillme im using a solas amita 4 blade prop that hit,s max rpm perfectully.

heres a pic of the boat without the motor on.its 17 foot.

 

[Mark_VTfisherman]

Re: Evinrude vs Mercury

I don't see the problem - you think you burned about 9 gallons with the Merc traveling 23.67 miles and you think you burned 6 - 7 gallons with the OMC traveling 23.44 miles. Sounds to me like the OMC is walking all over the Merc.

After reading the posts and seeing these last two I concur. I re-read the original post about four times doing the math after reading a few responses

I thought the Evinrude fuel consumption sounded great!

I don't know the size of the boat but any time I have been involved with a smaller outboard boat planing at speed, anything approaching 4mpg is above average. I hear that some newer equip. does better but I don't know anyone who has a new boat- we're all a little broke and have old stuff like you

I have not checked my boat with the '85 suzuki 40 but I did twice with my '64 Johnson 40 and optimistically managed about 3mpg at 26mph. The fewer times I have used my backup can since installing the Suzi suggest that it does a lot better.

 

[dieselcat]

Re: Evinrude vs Mercury

ok you all miss under stood me.I went 47 miles with the merc on 9 gal of gas.i went roughly 24 miles with the rude to the 9 gal of gas,that is a huge difference in gas usage.when i said it is 23.67 miles 1 way,then it would double inorder for me to get back home.Gas usage is round trip with both motors.

And the merc is a 4 cyl also not a 3.

 

[dieselcat]

Re: Evinrude vs Mercury

I don't see the problem - you think you burned about 9 gallons with the Merc traveling 23.67 miles and you think you burned 6 - 7 gallons with the OMC traveling 23.44 miles. Sounds to me like the OMC is walking all over the Merc.

i don't know where you came up with the 23.44 miles for the rude,when i typed that i went 11.72 miles 1 way,which would be just a little under 24 miles round trip,
the merc went 23.67 miles 1 way and about 48 miles round trip,
9 gal on rude=24 miles
9 gal merc=48 miles.......pretty big difference to me

O and the boat is a landau pro 17 aluminum bass boat
with a michigan wheel apollo ss prop,19 pitch

 

[Mark_VTfisherman]

Re: Evinrude vs Mercury

We could only go by what you typed. But now 6-7 gals is 9 gals?

I think you already made your mind up; you don't need us to confirm it.

 

[dieselcat]

Re: Evinrude vs Mercury

it just doesn't seem right that a motor with 15 more hp would burn almost double the gas?Sorry i should have explained that both motors where round trip not just 1 way,i can tell you this,the rude would have run out of gas before i got home compared to the merc which i still had plenty of gas after the 47 mile trip,a quarter tank left when i returned to the dock.

 

[Faztbullet]

Re: Evinrude vs Mercury

Ok ,you had the last year 4 cylinder inline(little tower of power).Still smaller cubes than Johnson.

 

[jay_merrill]

Re: Evinrude vs Mercury

i don't know where you came up with the 23.44 miles for the rude,when i typed that i went 11.72 miles 1 way,which would be just a little under 24 miles round trip,
the merc went 23.67 miles 1 way and about 48 miles round trip,
9 gal on rude=24 miles
9 gal merc=48 miles.......pretty big difference to me

O and the boat is a landau pro 17 aluminum bass boat
with a michigan wheel apollo ss prop,19 pitch

You didn't say that you went round trip with the Merc - you said one way.

Since you have clarified, I still wonder about your numbers. Your tank may hold 12 gallons, but it may hold 13 gallons. You burned "about: 3/4ths of a tank. One the Erude, you burned 6 - 7 gallons.

What if your tank is, in fact, 13 gallons. What if you really burned about 7/8ths of a tank with the Merc. What if you actually burned only 5 gallons with the Erude.

Now you've burned 11.4 gallons to travel 47.34 miles with the Merc, which equates to about 4.15 miles per gallon, and you've burned 5 gallons to travel 23.44 miles with the Erude, which equates to about 4.7 miles per gallon.

In fact, even if you burned 6 gallons with the Erude, you're still getting 3.91 miles per gallon. At 7 gallons, you would have gotten about 3.35 miles per gallon.

You may not agree with my numbers, but my point is that trying to determine fuel efficiency with estimated fuel consumption, which could be off significantly, isn't going to tell you much. Without a flow meter, the best you can do is to start a run with a topped off tank, make the run and then top off again to figure fuel burn very closely.

Right now, what you are reacting to is more perception than it is fact.

 

[dieselcat]

Re: Evinrude vs Mercury

JM,I know what you are saying and i understand completely.All i know is last year when i still had the merc on the boat i could fill it up with gas and make 3 round trips down river to where i go wich is 9.66 miles 1 way.I used the ruler on google earth to figure my mileage.And with the 88 spl rude that is on the boat now,i'd be lucky to make it home on the second trip.All i know is this rude sucks it down.Also with the merc i ran damn near WOT [39-41 mph]the whole time,Rude 3500-4000 [29-31 mph] whole time.Either there is a reason [problem why] this thing sucks so much gas or it's just the nature of it.I just want to know if it's normal for these rudes to be gas hogs,if so i'm going back to the merc.
Thanks,
Mike

 

[ddrieck]

Re: Evinrude vs Mercury

Yep, the Rude is not worth your time and pocket book. Go back to the Merc...then set the rude out front and I'll swing by and pick it up


Anyway...its all personal preference...go fast or save gas...its up to you.

 

[jay_merrill]

Re: Evinrude vs Mercury

I use the ruler in Google Earth to plot distances too -its very handy.

My suggestion is this - go run the ERude again, starting with a topped off tank. Run the boat over a predefined course that you have determined exact distance for. Then top off again to as close to the first level as you can get. Figure the consumption and mileage based on those things.

Between looking at simple hourly fuel burn at a given rpm/speed, and the mileage/economy info, we can get a better sense of what your motor is doing. In as much as the info gathered this way should be pretty accurate, we will have a better feeling of knowing exactly what the figures are and can offer a more informed opinion.

 

[crb478]

Re: Evinrude vs Mercury

JM,I know what you are saying and i understand completely.All i know is last year when i still had the merc on the boat i could fill it up with gas and make 3 round trips down river to where i go wich is 9.66 miles 1 way.I used the ruler on google earth to figure my mileage.And with the 88 spl rude that is on the boat now,i'd be lucky to make it home on the second trip.All i know is this rude sucks it down.Also with the merc i ran damn near WOT [39-41 mph]the whole time,Rude 3500-4000 [29-31 mph] whole time.Either there is a reason [problem why] this thing sucks so much gas or it's just the nature of it.I just want to know if it's normal for these rudes to be gas hogs,if so i'm going back to the merc.
Thanks,
Mike

Is the Rude a gas hog? Yes some what but I doudt that is what your problem is. How is the motor set up and what are your rpm's at wot? I personally think that you are probably lugging the motor some at 3500-4000 rpm. It should be more efficient in the 4800-5200 range and I would shoot for a wot of about 5800. Try to vary your speed to find the sweet spot for your motor, getting there quicker my well save you some fuel.

 

[56 rude]

Re: Evinrude vs Mercury

just one other suggestion to the above,if you have acess to a 17p prop try it out .ive found that my best performance bar none is with a 17p and ive also looked at several other boats,all different ,that had 90 rudes and they all were running a 17p prop.i have a buddy that has a 110 rude on a 18 foot aluminium boat that he had proped with a 19 or a 21 and that thing would use twice the fuel of my 90 in the exact same distance till he proped it properly.get the 90 to run as close as possible to rated wot or even slightly above and in good tune before you give up on her,their damn good motors.sorry crb posted mine just after your excellent suggestion.