61 Evinrude 40HP- no power/ burns tons of gas

[oldybutagoody]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

I'd say 24/1, not 50/1. Oil is cheap insurance and you'll never hurt it with too much oil but too little will.
My money says it runs WAY better since you adjusted the high speed needle. Your fuel economy will be better too but those old big twins do get thirsty. It will never be great.

Ok Guys- high speed needle was way out- i seated it gently and then backed out 3/4 turn, then i put another 1/8th turn so its set between 3/4 and a full turn- should be good for starting point- I'm going to guess that was the largest part of my problem and will be able to confirm that this weekend when i get out. When I bought this motor- I asked what the fuel oil mix was and was told 50:1. Today i seen a manual(thanks Bigkat) that shows 24:1 is the mix ratio. Thats a huge difference- i ran 50:1 the other day and it seemed ok other than the complete lack of power, but I'm concerned about the mix. What do you guys think?

 

[kfa4303]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

yup. You need to run 24:1 mix in your motor. running 50:1 will deprive the internals of lubrication. You're most likely loosing power due to a bad ignition which is causing the motor to loose spark to a cylinder, which is why you are using so much gas and only getting about half the power you should. You should be able to get a bright blue spark that can jump a 1/4" gap from each wire. If the coils have never been replaced, then one or both are certainly bad. You can get replacement coils and a tune up kit right here at iboats for about $20 each.

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm

http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

thanks guys- 24:1 it is. Im thinking my spark is good- it is bright blue and does easily jump 1/4" gap- havent tried an adjustable spark tester with a larger 7/16" gap but i'm guessing good there too- i will be checking to see if im dropping a cylinder but i have to think my high speed needle being so far out of adjustment was most likely the cause of all my problems from my last test. I'll keep you posted- on the water tomorrow, thanks again

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

woo hooo, thanks guys. i guess that says it all. at 1st, not much change- i started going in, then out with high speed needle and it didnt seem to make a huge difference. so i cut it, and decided to start over again- i think i stopped turning it in last time when i started ti feel resistance and never actually got it seated- this time i did and backed it out 3/4- fired it up and started fine tuning- i got it up to around 13-14 miles an hour, pretty much double what it had been. I figured i still had some fine tuning to do but was happy with that since it was pretty much as fast as that boats moved since i owned it. Now heres where it gets weird- at least for me...i decided to shut down and throw the cowl on so i could hear how it sounded with it on, when i started it back up and started down the lake- i got up to 20-21 mph- with me and the old man in er- im sure it'll do 30 with just one of us in it. Why the jump in power guys?? was it putting the cowl on that did it- or was it just shutting it off and starting it up again with the carb properly adjusted? in any case, i'm a happy camper at this point- round 2 hrs on the water and i burnt 3gals of fuel. Sweet!!

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

Heres a few vids if your interested- traveling a lot faster with the cowl on

http://youtu.be/nKHjUB0jLO4 - cowl off

http://youtu.be/zXHGNfayGqI- cowl on

 

[Willyclay]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

Why the jump in power guys??

Thanks for the videos. Great results with very little effort. RE your Q above, the motor is designed to run with the cowling on and access panel closed. I believe the noticeable difference in performance is produced by a very slight change in the airflow entering the carb and the resulting air/fuel ratio got closer to the "happy place", if not dead on it.

Are your speeds measured by GPS? If not, then be aware most speedometers are not accurate. The old Big Twins are good stump pullers but not speed demons. On a very lightly-loaded flat bottom boat, you might see 30MPH if compression is over 100PSI in both cylinders. The more, the merrier! Your 40 should run around 25MPH with no problem based on what I see in the video about your boat and two aboard. Good luck with that great old motor!

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

ya, getting my speed from a GPS. I'm very happy with the performance now, any more than that might be a little much for my boat anyways. Good to know i'm pretty much there with the speed/ performance of the motor. I was starting to think my boat was the problem but alls good now.

I'm planning on having this one for awhile so I'll be taking good care of it- should be good for many years to come. Thanks everyone for the help and suggestions

 

[oldybutagoody]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

Glad you got her goin'. That looks like a great lake to boat on. Thanks for the videos. WillyClay is spot on with the cowl advice.

ya, getting my speed from a GPS. I'm very happy with the performance now, any more than that might be a little much for my boat anyways. Good to know i'm pretty much there with the speed/ performance of the motor. I was starting to think my boat was the problem but alls good now.

I'm planning on having this one for awhile so I'll be taking good care of it- should be good for many years to come. Thanks everyone for the help and suggestions

 

[Willyclay]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

I'm planning on having this one for awhile so I'll be taking good care of it- should be good for many years to come. Thanks everyone for the help and suggestions

You might want to get a tach to verify the motor is running in the desired RPM range. Checkout the link below:

http://www.ebay.com/itm/Inductive-T...Parts_Accessories&vxp=mtr&hash=item1c1e0fa1ef#

If you are able to determine WOT RPM's, then you can decide if a prop change is necessary. Might be a couple more MPH's there. If you are concerned about the boat handling different at higher speeds, you might be a candidate for some Smart-Tabs. Good luck!

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

looks just like my tiny tach, lol. I havent wired it to this motor but I'm going out today so i'll attach it and see what my rpm's are. I'll post back with findings- what should it be? a manual i have here says 4500rpm so that should be accurate- my prop is 10.5 x 13, 384460- from what i can tell- its the right prop for the motor and previous owner also gave me a spare. I'll let you know,
thanks

 

[Willyclay]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

Just make sure your Tiny Tach is the correct model for two-stroke engines and 4,500RPM's is what my manual says also. Good luck!

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

ok, great day on the water. Tach says i'm doing around 3450rpm at WOT with 2 in the boat, thats 20.5mph. I dropped the old man at the dock and got an extra 100 rpm, so 3550 and picked up a bit of speed- 23 mph. So I guess I'm about 1000rpm under what i should be. What could cause that? weight? carb? prop? I'm guessing thats as much as I'm gonna get without switching props unless its a carb thing. Ran around 7 Gal's through it, its running great.

Whats the deal with smart tabs? What would be involved with adding them to my boat?

 

[kfa4303]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

The engine height may also be an issue. You want the anti-vent plate found just above the carb to be level, or slightly higher than the keel of the boat. Adjusting the tilt and trim can also help. You may also want to perform a link and sync on the carb. Do a search here in the forums for the procedure.

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

The engine height may also be an issue. You want the anti-vent plate found just above the carb to be level, or slightly higher than the keel of the boat. Adjusting the tilt and trim can also help. You may also want to perform a link and sync on the carb. Do a search here in the forums for the procedure.

I have a few questions about your post. 1st- the antivent plate- can you explain that a bit more- it it visible on the carb pics i posted earlier in this thread? I can Post a pic of the boat with motor down if that will help.

2nd- ive only got manual tilt/trim ie the movable bar that determines where the motor sits- ive tried 2 different spots- I've tried one out from all the way in(all the way looks like its in too far) and another past that which seemed to keep my bow a little high. Willyclay mentioned smart tabs- something i may have to look into.

3rd- and i may be way off base here- but i figured a link and sync was for multiple carbs. is that not the case? Thanks for the advice

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

ok, link and sync- not just for multiple carbs- ive read a few different procedure in a pdf manual i have but it's not very clear- not at the moment anyway. Can i check to see if its synced without actually doing the procedure? Is the main idea making sure the throttle plate is horizontal(wide open) when at full throttle? I'm gonna go out and have a look now

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

ok, checked it out- im not getting full open when at full throttle- heres a vid that should clear things up- i should also note that i takes a lot of force to get it to full throttle and seems to be spring loaded as it will back off if not held in place. I'd love to get this straightened out.

http://youtu.be/k3DQPr53eNY

 

[Willyclay]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

You are right on target to get it fixed! Not sure what service info you have but the link below will get you to one paragraph in a non-factory manual which with the diagrams included should let you reach your goal. Good luck!

http://forums.iboats.com/showthread.php?t=393281

LOGIN as directed then drill down to: Small Engines, Marine/Boat Motors, Evinrude/Johnson, Outboard 40HP (1956-1964) and, finally, Condensed Service Data. Your linkage looks like the "later model" to me when selecting adjustment procedures.

 

[Willyclay]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

It may just be me but when I looked at your video again, the "cam follower" (roller thingie) does not appear to be moving when your exercise the carb throttle plate linkage and I believe it should. I do not currently have a Big Twin so am working off geezer memory and my old book. Take a look at the parts diagram at the link below and see if you can identify something in that linkage that is missing. Hang in there, it's usually the simple stuff!

http://www.marineengine.com/parts/v...evinrude-johnson/ITEM_2515/ITEM_251500001.htm

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

just had a look at the parts listing- i think it is all there- the roller comes into contact with the armature plate when it advances with the throttle- in my video, i'm using just the throttle to show where its full open position is- if i had been cycling the throttle cable the armature would move and contact the roller. I'll take a better vid when the weather here clears up. Thanks again- that's the exact manual i've been looking at too

 

[matth121]

Re: 61 Evinrude 40HP- no power/ burns tons of gas

if you look at the vid again- good shot of the cam follower at 1:04- if you notice- theres a line across the middle of the follower where its contacting the armature plate- and if you look at the plate itself- the edge that contacts the follower is very shiny