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1974 65 hp 650 merc wont start

suso

New member
I have a 1974 65 hp merc that has new fuel, good compression and wont start.?? I had it out at the lake put it in the water started up right away ran pretty good. battery was almost dead so after letting it run for a couple minutes i shut it off and charged the battery. after that it would not start at all???? cant figure it out at all.i have put fuel directly into the cylinder using spray bottle and still nothing.compression is 120 in all 3 cylinders and is getting great spark. really strange that with good spark, good compression and fresh fuel in cylinders that it wont fire?? it does back fire when cranking it over.!!?we took carbs off and they looked really good too. could the timming have slipped somehow??:confused: any advise would be helpful. thanks.
 
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You said the battery was almost dead - and you took it out to the lake?! Did you get back? I learned that normal battery can
now last 6,7 years easy with pro rate warranty, however, for marine battery, at most they will give you 2 to 3 years.
Check the battery, and if possible, check the battery voltage while you are cranking. If less than 9 1/2 volt, you may have
to repair the starter.
 
I did some paddling!
last night i replaced the needle and seat thinking it could have something to do with it but it did not.I keep checking the spark plugs to see if they are wet with fuel and they are constantly dry after cranking engine over and over.A friend of mine says the only thing that makes sense of there being no fuel to the plugs is the reids, bent or broken?it is a older motor and it hasn't really been run in the past 4 yrs.!! i went out and bought a new battery aswell so I know there is lots of cranking power.
 
Pull the carbs and you'll be able to see the reeds.Probably sticking push on them gently with a pencil or something just enough to open them. If it allows your motor to work so much the better.If not you'll need to split the crank case and clean/replace them.
 
Are u sure your getting fuel to the carbs.Have you checked that your fuel pumps working.When you pump up the gas bowl is it getting hard.The timing would be ok unless you moved it,they just don't slip.
 
oh ya, lots of fuel to carbs! it comes pouring out the front and nothing gets back into cylinders. primer ball does get hard and bowls fill up. is it possible that 1 or 2 or all 3 reeds are failing or broken, it hasnt run in @ 4 yrs.???
 
pull the carbs and rebuild each one. Fuel pouring out of a carb is NOT acceptable!!! If rebuilding those carbs is not your cup of tea, get someone to help. They are a precision part, not something to just take apart and throw together.
 
And when you get done rebuilding the carbs, clamp each one in a vise and pressure feed it with gas to ensure it's not leaking. Why? As you'll discover, that motor's carbs are a DOG to work on. I have a special, ground down and bent 7/16 open end I use on them. Oh, and be sure the nuts are free spinning BEFORE putting the carbs back on Make them go on easily with you fingertips instead of trying to rotate them with the wrench, especially that lower b*st*rd on the right side!

Jeff
 
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