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Leak down importance

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moore940

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"I been reading that you can h

"I been reading that you can have good even conpression but if the leak down is bad you will have a impossible task getting your engine to idle, witch my 1978 johnson 70hp wont idle. leak down absolutely bad, compression 138-138-140, carbs rebuilt and clean Just need to know and if leak down is very important where or who do you recomend to buy a rebuilt powwerhead thanks"
 
"with compression #'s like

"with compression #'s like that,..i would'nt even pull my leakdown tester out.... your idle problem,..may very well be ign or carbs,or adj between the 2."
 
Thanks JWMarine I have cleaned

Thanks JWMarine I have cleaned and rebuilt carbs. did linknsync .new plugs CHecked firing. runs great at high Rpms just not at low rpms new reeds Kinda frustrated
 
"tell us about your bad leakdo

"tell us about your bad leakdown specs...,but,...there are some rejetting things u can do too... but,... dont create prob's for yourself... your comp #'s are great..."
 
"While doing the leak down the

"While doing the leak down the top and bottom cyl pretty much went to zero the middle held just a little longer then zero . but was much harder to hold engine from rotating. been a mechanic for 30years on large industrial engines just work on boat motors for fun,they seem a little more picky than the big ones.Ha"
 
Did you position the piston pr

Did you position the piston properly for the leakdown test on the upper and lower?????
 
"I guess just by reading the

"I guess just by reading the next to the last post by me, it seems I must be a litle off in the head, well I am kinda embarrased while doing leak down trying to hold the engine from rotating I kept turning air supply off. rechecked with my helper (wife) found leak down very good 1-6% 2-6% 3-8% base 100psi now about that idle problem and yes I was creating my own problem I guess by making a dumb mistake. I want to thak yall for the help probaly need more I enjoy the foum"
 
"good deal!... now,..determine

"good deal!... now,..determine,if your idle prob,is fuel or ignition,related,and persue accordingly.If u have dibris in an idle passage,..u would lose 1 cyl at idle,etc.while idling,w/breather off,..u can use a rag or your hand,and slowly,lightly cover the carbs one at a time to see if it picks up.U can get the see thru 'sparky's',at an auto parts store,...to monitor idle ign....just a few thoughts for u."
 
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