Logo
FULL SITE MENU

fuel consuption

4

48tony

Regular Contributor
I have a older johnson 60 hp 1970 esl-d.The other day I put 6 gall in the tank and went on the water . I pulled a tube for a while then just romped around for about 3 hrs in this time i must of burnt about 4 gall of gas. Does this seem about right?The boat size is a 14 ft fiberglass a bit on the heavy side do to all my gear.The moter is running well I do have the carbs adjusted on the rich side could this cause more fuel consumption?
 
Sounds OK to me.
I have 73' 65HP and I always carry 2 tanks.
Usually one 6 and one 3 gallon.
I easily eat a 6 gal tank in a 4-5 hr day.
17' 1200 lb boat though.
 
jim18611865 said:
Sounds OK to me.
I have 73' 65HP and I always carry 2 tanks.
Usually one 6 and one 3 gallon.
I easily eat a 6 gal tank in a 4-5 hr day.
17' 1200 lb boat though.
Click to expand...
Thanks jim Iguess thats about what i get maybe leaning out my carbs a we bit may help.
 
This link has an attachment for a fuel consumption chart at various rpms that includes gph, mph, mpg curves.
This engine is the same vintage as yours but 115 hp. The boat info is given. You should do better than this, but can give you an idea. Load is load regardless of the engine potential power.
 

Attachments

  • Performance Data.pdf
    15 KB · Views: 826
Last edited:
tboltmike said:
This link has an attachment for a fuel consumption chart at various rpms that includes gph, mph, mpg curves.
This engine is the same vintage as yours but 115 hp. The boat info is given. You should do better than this, but can give you an idea. Load is load regardless of the engine potential power.
Click to expand...
mike thanks for the gas chart .I guess these old motors were not built with fuel savings in mind. they are gas hogs but when the cost is up to 5 a gallon they pinch the pocket .If we play we pay.But when it comes to being out on the water is there really any value we can put on the enjoyment.It could be 10 a gallon and i will still be out on my boat. Thanks Tony
 
kimcrwbr1 said:
Oh yea keep you hull good and clean and a good prop makes a big difference for performance especially!
Click to expand...
I keep it pretty clean and wax it often.as you speak of good prop i am working with a guy that sells power tech props.the prop i had on was a 13 3/4 x 15 at wide open the rpm was about 4700 at 30 mph. I want my rpm at about 5500.He sent me a alum 14 x 13 and gained very little rpm.So next i will try a 14 x 11 this should get my rpm up.after we find witch prop works best on my boat i am going stainless,so this should be a good leaning prosses with fitting a correct prop
 
There is something wrong with the picture !!------A 14' fibreglass boat should not need a 13 " or 11" pitch prop.---------Find out why your boat will not perform with the 15" prop !!!!!!!!!!!!!!!--------Perhaps your boat has foam flotation that is waterlogged, seen it many times.
 
racerone said:
There is something wrong with the picture !!------A 14' fibreglass boat should not need a 13 " or 11" pitch prop.---------Find out why your boat will not perform with the 15" prop !!!!!!!!!!!!!!!--------Perhaps your boat has foam flotation that is waterlogged, seen it many times.
Click to expand...
Hi racer,I bought this boat a couple years ago and it had not seen water for some time.I put this 60 hp on it and the prop that was on it was 13 x 19 this prop did not give me the rpms so I bought a turning point prop last year 13 3/4 x 15 it helped with the rpm range butt felt 47-4900 was still a bit low.So this last prop change i did was going from a 13 3/4 dia to a 14 in dia to 13 pitch with very little change.I just put a 14 x 11 pitch on it butt have yet to try it on the water.My boat has 2 batt 6 gallon tank and other gear so i would say it is on the heavy side.if this 11 pitch does not change the rpm then i will be concern with a problem. as you said my boat does have the foam up in the upper part of the bow but it is all dry the problem may be in the lower part of the bow were i can not see if it is water logged.so you feel that running this low pitch prop indicates a weight isue.how could i find this out put it on a weight scale .I would have no clue to what a 14 ft fibergls would way.do you have a ball park#.and lets say your correct with it being water logged in the lower bow the foam is casted under the fiberglass how could i fix it? thanks for the feedback racer.
 
I've got a 73 50hp Evinrude on a 1973 15 foot f/g runabout. It's turning a 13 3/4 by 17 prop at between 5200 to 5600 rpm, depending on which tach you believe. A 19 pitch brought it down to about 4800 rpm. According to my GPS, I'm running right at 30 mph with the 17 prop. So, unless you are waterlogged as suggested, or you just have a really bad hull design, maybe you have engine problems. I'd be checking the compression first of all, then timing and carb syncronization.
 
Fact ---There is perhaps something wrong with the boat.-------------Or perhaps something wrong with the motor --------Or perhaps something wrong with the tachometer.--------------Couple of gas tanks / batteries does not make a boat " heavy " to require an 11 " prop.-----Time to do research.
 
bill_w said:
I've got a 73 50hp Evinrude on a 1973 15 foot f/g runabout. It's turning a 13 3/4 by 17 prop at between 5200 to 5600 rpm, depending on which tach you believe. A 19 pitch brought it down to about 4800 rpm. According to my GPS, I'm running right at 30 mph with the 17 prop. So, unless you are waterlogged as suggested, or you just have a really bad hull design, maybe you have engine problems. I'd be checking the compression first of all, then timing and carb syncronization.
Click to expand...
hi bill, i am unsure what to think at this point.i just did a full rebuild on this 60 hp comp 120 on all 3 holes. good spark.maybe my tack is off butt i would hear the motor over reving and with all these props ive been changing the rpms have not made the motor sound like its been over reving,i think i might have to put it in the shop and have it looked at.
 
Bottom line, as Racer said, is that something is wrong somewhere. It really sounds to me like the tach is off. With your 15 pitch prop, 30 mph is in the ball park. I was running a 15 inch prop last year, and didn't have a tach on it. When I installed the tach, it was turning about 5800 to 6000 rpm. I couldn't tell the difference between that and the 5200 to 5600 its turning now. What speed are you getting from the 13inch prop?
 
bill_w said:
Bottom line, as Racer said, is that something is wrong somewhere. It really sounds to me like the tach is off. With your 15 pitch prop, 30 mph is in the ball park. I was running a 15 inch prop last year, and didn't have a tach on it. When I installed the tach, it was turning about 5800 to 6000 rpm. I couldn't tell the difference between that and the 5200 to 5600 its turning now. What speed are you getting from the 13inch prop?
Click to expand...
my speed is around 30 mph and that speed has not changed from one prop to the other 30mph with the 15 ,13 yet to run the 11 pitch.Ya i hope it is just a bad tack. is there a way to hook up a shop tack and run it on the water to see if it is reading diferent from my dash mont .allso i was thinking my bow stands up pretty hi when i go to plane if it was waterlogged in the bow wouldent it just plow and not stand the bow up.even runnigat 25-3000 rpm the bow stands way up untill i throttle up to plane.Allso is it possible for my tack to give me correct reading at low rpm and then go out of wack at my top end?I really dont think i have a motor problem because it has good power and to get up to 30 mph the motor purrs.Iwill check the tack and get back with some info.and thank you for the help every one.
 
do you have power trim on this motor?if not have you tried moving the pin a hole closer to the transom?....where is the cavitation plate in reference to the bottom of the boat?
 
papyson said:
do you have power trim on this motor?if not have you tried moving the pin a hole closer to the transom?....where is the cavitation plate in reference to the bottom of the boat?
Click to expand...
hi, guyies well i took it out on the water again with a 14x11 prop the prop ran real bad the 14 in felt like it was lugging the motor it would get up out of the hole but i could feel the prop just not gripping allthough the rpm did go to 5200 but the motor just lugged and it took a while to get it to full speed do to no prop bite in the water.I had a prop my friend let me use it was 13 x19 this prop ran a little better but again with the 13 dia it was not getting the grip in the water out of the hole.this motor does not have t/t and i have the transom pin in the 4 th hole the cav plate is pretty level with the bottom of the boat.if i change the pin to a lower hole do you think it will help. i am puttin the 13 3/4 x 15 back on this prop seems to run best nice bite out of the hole and smooth through low and hi rpm. but at wide open i only get 4800 on tack.I was thinking maybe my timming may need to be adjusted.the moter starts up nice and idles good.if the timming is off would it still do this?What i thought was going to be a simple prop change has lead to be a chalenge.
 
You need to determine what is going on.-----------Serious engine damage can result from wrong timing, lugging or over revving the motor.
 
racerone said:
You need to determine what is going on.-----------Serious engine damage can result from wrong timing, lugging or over revving the motor.
Click to expand...
today i will put a timming light on it and see what the timming is set at my book says set at 22 degrees at 43-4600 rpms.when i first put the motor on last year i timed it out on the water and i got it right on. but since then i did put a new regulator -rectofier on it .i bought this to regulate the system as this older 60 hp was unregulated so cdi sold me a reg/rec.would this have caused my timming to change.I guess by putting a light on it today will tell me
 
agree on hole change and i think the 15 inch prop is probably where i would stay....a 13 is too much and a 17 wont get out of the hole....just my opinion
 
Back
Top