1957 35hp evinrude bigtwin wont idle

[boatguyneedshelp]

hello I have a 1957' 35 hp evinrude big twin motor.. it runs but will not idle at a low rpm nor will the second cylinder kick in. Ive replaced the points in it and it did not seem to help. both cylinders are getting good compression. Im thinking maybe the valve adjustment is off. If anybody knows anything about this style of motor pleas help.

 

[tashasdaddy]

Re: 1957 35hp evinrude bigtwin wont idle

do you have spark on the second cylinder, what is good compression? it has single carb that supplies fuel to both cylinders, so should not be carb.

 

[boatguyneedshelp]

Re: 1957 35hp evinrude bigtwin wont idle

yes both cylinders are firing when I say good compression I mean that I did the finger over the plug hole test and it felt the same on both. The bottom cylinder is firing so I assumed the top was good as well. when I get it runnig and put it into drive I can adjust the fuel air mixture extremely rich to activate the second cylinder but then when I bring it back down to an idle it stalls immediatly.

 

[tashasdaddy]

Re: 1957 35hp evinrude bigtwin wont idle

finger over hole is not a compression test. if you do not have proper compression, anything you do is a waste. do a proper compression test, and see if you have a viable base to work on.
http://forums.iboats.com/showthread.php?t=167352

 

[ryendube]

Re: 1957 35hp evinrude bigtwin wont idle

tash is right need to check compression properly, also you said you assumed top was firing? did you actually check? adjusting carb isnt going to "activate" the secound cylinder. carb doesnt diferentiate between cylinders, it pukes mix into them both.

I found mine was finicky as hell to get to idle properly as the low speed adjust was sloppy. theres a sticky on how to properly adjust your needles in this forum.Did you follow that procedure? aswell they dont idle that smoothly regardless. i wouldnt expect it to "purr" at idle.

 

[dthrckt]

Re: 1957 35hp evinrude bigtwin wont idle

i wouldnt expect it to "purr" at idle.

haha - must be lucky cuz mine idles right down really well...can almost troll, and it is a light boat

but yeah it sure is far from a "purr" - thing looks like it will shake itself right off the boat lol

anyway, i'm certainly not as qualified as the experts that have chimed in, but might it be possible for the spark to be present, but weak on one cylinder, thus only causing detonation if the mixture is just right?

 

[boatguyneedshelp]

Re: 1957 35hp evinrude bigtwin wont idle

hello thank you every one for your input... I adjusted the carb as it said on the form you sent me and it ran great both cylinders sounded good it wasnt poping or studering then after about 5 minutes it died I spoke with someone today who said that it could possibly be the oil I am mixing I am using a brand called international at a 32/1 mixture.. could this cause it to foul the plugs and stall like this ?

thanks again everyone.

 

[tashasdaddy]

Re: 1957 35hp evinrude bigtwin wont idle

you should be mixing 24: 1 using TC-W3 rated outboard oil. never heard of international oil. also using Champion spark plugs JC6 gapped at .030

 

[boatguyneedshelp]

Re: 1957 35hp evinrude bigtwin wont idle

thank you for the mixture info I apreciate it now I have no spark at all out of either coil the coils are old so I think that is probably the problem. is their a ground wire I am missing?

.. thank you again for all the help

 

[lindy46]

Re: 1957 35hp evinrude bigtwin wont idle

Replace coils

 

[boatguyneedshelp]

Re: 1957 35hp evinrude bigtwin wont idle

ok this keeps getting deeper.. I have found now that in order to get spark again I must spin the crank shaft counter clock wise.. this is backwards to how the pull cord is set up. any Ideas? cuz I am completely out of my league and have no clue... the only thing I could imagen is that I have some how reversed polarity on the flywheel.?.?

 

[boatguyneedshelp]

Re: 1957 35hp evinrude bigtwin wont idle

nevermind I found the problem the key was sheerd almost completely off causing the flywheel to set wrong after I replaced that (along with coils, condincers, plugs, wires, flywheel, fuel and air lines) it ran great. oh and the proper fuel mixture with some better oil.. I dont care what anyone says this motor is a champ! and it CAN purr I took it out and could troll with it! lots of power too. the only down side is the fuel economy not so great on gas... thats ok tho.
thanks everyone for all the help.

 

[lindy46]

Re: 1957 35hp evinrude bigtwin wont idle

Make sure you torque that flywheel nut to 60-65ft.lbs or you will shear the key again.

 

[tmcalavy]

Re: 1957 35hp evinrude bigtwin wont idle

Simple and reliable...that's why so many are still in service today...are you listening Ford/GM/Chrysler?

 

[dthrckt]

Re: 1957 35hp evinrude bigtwin wont idle

i was just looking at the bigtwin section of my outboard repair manual - the notes on the vacuum cutout switch stated that if the lower cylinder isn't firing a wire for the switch maybe grounded out.

I know that wasn't your problem but thought i'd post it in case somebody else has a cylinder not firing, like you did. although, if you had this problem i guess you wouldn't have spark.

congratulations on your motor. i absolutely love mine. not only are they reliable but you can buy parts motors for next to nothing, and there are so many people out there w/ a lot of experience w/ them (and a willingness to help) that it is usually pretty easy to find a detailed answer on any issues...

 

[boatguyneedshelp]

Re: 1957 35hp evinrude bigtwin wont idle

thanx for the torque specs. and you are right it is a great motor I had a tube behind it and it did great. I couldnt beleive it. lol thanx for all of your help everyone this is a great site.!.!

 

[ryendube]

Re: 1957 35hp evinrude bigtwin wont idle

wow what kind of boat are you using it on to to be able to tube with it?

Mines on a 16ft trihull bow rider. it just has enough power to plane out. if i put 3 full size guys onboard, putt putt putt..... sokay though its for fishing on a lil lake system.15sqkm.