115 new power head

[autodog2]

replaced powerhead now with 140!rejet,spark plug, fuel lines, and oil to book spec. for 140.o/b is 1982 20". I thoughtthe vibration was there before repower but not sure. old moter had a bad head gaskit and bad piston but i did notice that the tack jumped from time to time.finall put my dwell meter on all spark plug and found #2 plug firing twice as fast as other (old head). now new head;runs like bat out of h***!Problem:when at steady rpm there is a vib like a miss and tack still jumps from time to time esp. at 3000.no vib when acc. smoth at any rpm and plenty of power!No hestation jumps out hole and snaps neck with ease.Two houre brake in done will go to 5000 aswom couldnt stay there to level out so dont know if vib is there.im running duble oil for brake in.Motor responds with gentless throt movement!lighting fast! autodog@aol.com

 

[ezeke]

Re: 115 new power head

Are you using a teleflex tach?

 

[autodog2]

Re: 115 new power head

no i am using the factery tack

 

[rodbolt]

Re: 115 new power head

great you got it rolling. the tach problem may not be ign related. the tach is powered by the charghing circuit.has nothing to do with ignition.look for any loose wires. does the engine cut out with the tach ? if the engine is smooth and the tach is jumpy start chasing connections/switches<br /> good luck and keep posting

 

[Solittle]

Re: 115 new power head

Might want to get some more info on the brake in. I think two hours is a bit short. Ten hours are what some folks recommend.

 

[walleyehed]

Re: 115 new power head

OMC-Bombardier.......10hrs break-in...first 30 min. most critical. Don't run at 5000 RPM for more than a few seconds for the next 2-3 hrs.<br />Actually, 5500....5000 is OK, just vary throttle settings, and don't run WFO for more than a few seconds or alittle longer as time progresses.

 

[autodog2]

Re: 115 new power head

ya guys the book says not to run past 3000 for first two houres and not to run longer then 10 sec. above 3000 for the next 8 houres wich makes a total of 10 houres brake in.OK now for tack the engine dosnt cut out it just has a viberation at constent rpm.Now sence i put a140 power head i change the jets to 140 like the book called for.jets are (hs)from 60c (old) to 67c (140) and idle jets are .034iab to .036iab (140).Do you thank i could be making a rich mixture because carbs re the same?