what spark plug to use?

[b.gagnon]

what spark plug to use?<br />I have a 1978 70hp chrysler and all the books at the auto store jumps over this year.<br />I have a fouling problem and want to make sure I am using the right plug.

 

[b.gagnon]

Re: what spark plug to use?

Just looked up the mod# and it is a 79....Thanx

 

[eurolarva]

Re: what spark plug to use?

Book says all three cylinder chryslers are a champion L20V. I dont know if they still make this plug however a NAPA or Autozone should have a cross reference to it.

 

[b.gagnon]

Re: what spark plug to use?

I Have done some research and still have a few questions.<br />Chrysler 70hp<br />Mod#709h9a<br />Serial#2192<br />I Think it is a 1979<br />Has L 20v Champion plugs in it<br />Has Magna power Ignition (Not magnapowerII)<br />Is this the right plug for this motor?<br />NGK calls for a BUHW or BUHWII(hotter)<br />Champion calls for a #811 (which looks totally wrong)<br />I generally go trolling speed for extended periods of time (no wake speed) and this is causing the plugs to foul. After using the search feature for this forum it is my understanding that a champion L76v seems to be the right plug with a L78v being one step hotter? Could I use the hotter plug, and would I risk doing any damage to the motor?<br />The motor runs great if you don’t go slow for too long, <br />The mixture screws are set at one full turn(nervous to go in any more) and the compression is an even 120psi on all cyls… I’m sorry to ramble on but this is driving me crazy!

 

[eurolarva]

Re: what spark plug to use?

I would stick with the L20V if you can get them. I have read posts concerning the L76 and according to Champion they have the same problem with fouling as the L20V. Going to a L78V will burn hotter and have less problems with fouling however at higher speeds this may not be good for the motor. Have you tried frequent decarbing and making sure the recirculation system is running correctly? Only use high quality Marine oil. Other reasons for fouling plugs is weak spark which could be an ignition problem.

 

[b.gagnon]

Re: what spark plug to use?

Do you think I will have any better luck with NGK?

 

[eurolarva]

Re: what spark plug to use?

You can try them. Gapless plugs are notorious for fouling. I cant understand why chrysler and force ever started using them. In a four stroke they are probably fine but two strokes produce so much carbon that is dont make any sense to use them.

 

[Realgun]

Re: what spark plug to use?

I actually like the NKG plugs. They work pretty well in trolling situations. At least they last longer. I know its time to change plugs when a push on the key and a turn don't get it to start right away.

 

[Tiger123245]

Re: what spark plug to use?

If NAPA or Autozone don't have the plugs you need, try O'Reilly's. I went to about 5 different stores before O'Reilly's and they were the only ones who actually carried Marine supplies/parts.

 

[timmathis]

Re: what spark plug to use?

Decarb and try mid grade fuel with ngk's.

 

[b.gagnon]

Re: what spark plug to use?

Well, I re-adjusted the carbs and put new champs in and it worked for about an hour. For two more trips I cleaned them and they did the same thing. I then put NGK's in and 5 times out now without a skip!

 

[imported_bjs]

Re: what spark plug to use?

ngk are far better plugs.but i have a 1998 force 120 plugs are champion been in the motor for a year with no problems. aviod buying plugs at wal-mart there not as good.as for fouling you may have other problems.try a differnt brand of oil.mix the oil correctly.ouicksilver is better than walmart brand.my motor smoke alot less with quicksilver.i buy my oil at sams.