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Archive through August 13 2000

ben

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" I have a tohatsu/nissan 70 H

" I have a tohatsu/nissan 70 HP motor 2 stoke 2 cylinder 1991. It just started to backfire evey 15 sec. at an idle. but at full speed it gos away, but it backfires so hard its blew-up my fuel-pump, and then the lower gasket. It has good compression, and I checked all the seals are good no air leaks, I also checked the carbs, no problem there, also the reeds are ok. I adjusted the timming a little and that help a little, but the backfires are getting worse the more I drive it. Also the motor dosnt always backfire just about 85% of the time. I don't want to adjust the timming to much because it used to run fine just the way it was. "
 
Try adjusting the syncronizat

Try adjusting the syncronization of the throttle plates-that is make sure that all throttle plates are closed at the same time and begin to open at the same time.
Tom
 
" Backfiring can also be ignit

" Backfiring can also be ignition system related and, other than timing, you haven't mentioned any checks done in this area. I don't know much detail about the components of your ignition system on this engine but inductive pickups (as are often used to generate ignition impulse signals to the ignition coils) have variable output (stronger voltage pulse at higher rpm and relatively low at low speed) so if one of those gets weak, it can show up as misfire or backfire at idle but not above idle speed. "
 
find the cyl that is misfirin

find the cyl that is misfiring than replace that cyl powerpack- if only one controls all three cyl
replace it-Will at old iron inc.
 
try changing your spark plugs

try changing your spark plugs
 
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