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5 hp 1990 Nissan 2 Stroke Low Compression Runs Good

9nick0

Member
I bought a 1990 Nissan motor in actually really good condition except for the compression numbers are barely getting to 60. It starts up fine, runs wide open fine but won’t idle or slow down enough for a smooth shift. Any recommendations? Running some seafoam through now as well as some carb cleaner.
 
The decompressor may have that pulling-only compression reading low. Give the seafoam to someone you don't like; it's just mineral spirits.
Remove the carb, completely disassemble, do a proper overnight soak of all hard bits, then blow out all passages with generic carb spray and reassemble.
 
Ok, do you think something else could be causing the low readings? Still waiting on the carb dip for this one. Ran some seafoam and power tune through it and it is doing slightly better at idle.
 
Try a decarbon treatment, and it may run better. Low compression on a 2-stroke is usually rings.
 
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