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1988 40 HP Johnson VRO stutters slow speed

S

spointer

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" My 40 HP Johnson VRO (19

" My 40 HP Johnson VRO (1988) stutters at slow speed. It is not missing but very rough run until past 1/3 throttle. Runs perfect past that point. Just had Carbs rebuilt. Occasionally, it runs good at slow speed too but not usually. Plugs replaced recently. Any suggestions? "
 
Do a compression test and pos

Do a compression test and post results for us to diagnose the problem.
 
" Sparky,
Compression is 149

" Sparky,
Compression is 149 in top cyl and 150 in bottom. Motor is older (1988) but has very few hours. It sat more than ran until I bought it last year. Runs like a top at higher speeds. Reed valves? "
 
Compression is good. Make sur

Compression is good. Make sure that the carburetors are synchronised with ignition and at idle both throttle plates must be closed.Remove the front cover and check that both throttle plates are completely closed at the same time.It may be that the low speed jets need adjusting.
 
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