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1990 70hp idle

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tmgrant

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I have a 1990 70hp Johnson on a 20 ft pontoon boat. When I put it in the water it starts fine and runs great as long as I keep it running. When I go to the dock to load it, it will not idle and it is next to impossible to get it on my trailer. When at home it starts right up and runs great. What's wrong with it?
 
its adidcted to the hose or its a homely and dont want to leave. break it for it breaks you. after careful adj of idle mix,sync,and timing, it may obey but if not you will have the old motor blues..... no security needed if its a pain to get goin. only you will have the combo.
 
Step # 1 is a compression test !------------------Has the tell-tale fitting on the block been modified as per the factory service bulletin ????
 
tmgrant
1990 70hp idle
I have a 1990 70hp Johnson on a 20 ft pontoon boat. When I put it in the water it starts fine and runs great as long as I keep it running. When I go to the dock to load it, it will not idle and it is next to impossible to get it on my trailer. When at home it starts right up and runs great. What's wrong with it? Did a compression test and all three cylinders have over 95 lbs pressure.
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Has the cooling system modification been done ?--------The carburetors are shown to have low speed mixture adjustment needles , have you tried adjusting those ?-----------Are carburetor throttle plates closed at idle ?-------- Have reed valves been checked ?---------Then again it might be as simple as just bumping up the idle speed !--Have you checked that spark will jump a gap of 7/16" on all 3 cylinders ?
 
Remove the carburators and clean them all (best is it to installe carb repair kits). Then install them and adjust the idle needles, while the engine is running.
 
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