1975 70hp evinrude wont fire after carb rebuild

Bob427

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Jun 20, 2010
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I have been playing around with this engine for a while now
when i first got it i tried to start it well the floats where messed up so i decided to rebuild the carbs

1.it did run for a few seconds before the rebuild it back fired out the exhaust
then flooded
2.I then checked for spark good on all cylinders
3. checked compression good and even on all cylinders about 125psi
4. rebuilt carbs
5.replaced fuel pump just in case
6.tried to start
7.seems like no gas is getting to plugs they are bone dry
8.now gas is starting to spit out the front of the carbs

all most like the is no crankcase vacum

any help with this would be great

thanks Bob
 

Fisher freak

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Jun 4, 2010
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Re: 1975 evinrude wont fire after carb rebuild

Re: 1975 evinrude wont fire after carb rebuild

you could have a intake leak and check the timing :) is their fuel coming from the carb jets?


what type of carb? make and modal
 
Last edited:

Daviet

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Sep 24, 2008
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Re: 1975 evinrude wont fire after carb rebuild

Re: 1975 evinrude wont fire after carb rebuild

What are we working on?
 

Fisher freak

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Re: 1975 evinrude wont fire after carb rebuild

Re: 1975 evinrude wont fire after carb rebuild

carb
 

glassmaster68

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Feb 17, 2010
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Re: 1975 evinrude wont fire after carb rebuild

Re: 1975 evinrude wont fire after carb rebuild

1975 Evinrude what? Gas flooding out the front of your carbs sounds like floats hung open.Are you sure theyre opening and closing/seating properly?Did you do link and sync after the rebuild?
 

Bob427

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Re: 1975 evinrude wont fire after carb rebuild

Re: 1975 evinrude wont fire after carb rebuild

sorry forgot the hp 70
model number 70573 e
 

Bob427

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Jun 20, 2010
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155
Re: 1975 70hp evinrude wont fire after carb rebuild

i checked the float level 3 times and made sure they where not binding before putting it back together

all linkage hooked up exactly how it came apart

will have to check to see if the jets are sqruiting
 

Bob427

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Jun 20, 2010
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Re: 1975 70hp evinrude wont fire after carb rebuild

bump
 

joey nathan

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Mar 17, 2009
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Re: 1975 70hp evinrude wont fire after carb rebuild

Bob,
I have this engine as well. Carefully check routing of the fuel line from pump to middle carb. It can get pinched between silencer and the engine if not careful. When you look you'll see an opening in the silencer for the hose. I made my fuel line a little extra long so it's not kinked at the carb and allows enough length to route through the opening in the silencer body. This is an awesome engine when running correctly, Good Luck...
 

glassmaster68

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Feb 17, 2010
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Re: 1975 70hp evinrude wont fire after carb rebuild

After putting the bowls back on the carbs,did you blow into the fuel intake with the carb right side up[and you could blow through it]and then turn the carb upside down and blow into it[you shouldnt be able to blow through it as the float/ needle valve should be closed],,,, if you can blow through it while upside down,your float is catching on something,gasket,inside of bowl,pivot pin might have a catch on it,,or the needle valve has trash in it,or needle valve could be mis aligning with the seat.,,,,so there are quite a few things that can cause float problems,,,,also one overlooked simple thing,,,make sure the spring that holds your needle valve to your float is holding the needle valve snuggly to the bottom of the float to insure it is moving right and tight with it.
 

Bob427

Petty Officer 2nd Class
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Jun 20, 2010
Messages
155
Re: 1975 70hp evinrude wont fire after carb rebuild

update:
got it to fire up today just wont stay running
i think i will look into the floats again
and i think i may have a coil pack that may not be 100%

thankyou everyone for your help

i will keep anding updates on progress

Bob
 

Bob427

Petty Officer 2nd Class
Joined
Jun 20, 2010
Messages
155
Re: 1975 70hp evinrude wont fire after carb rebuild

update

well she does run now but cant keep her running
it seems like it breaks up when you rev it

the spark seems alittle weak

think i may try a power pack next

sound like a good idea


thanks Bob
 
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