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70 hp dies at idle in gear

F

fredbriggs

Member
Have had this problem ever since motor came out of shop after complete overhaul. Engine will not idle in gear. Have sync all carbs with ball gauge, linkage adjustment to cam adjusted. Timing set at 4 deg, ATDC, but idle only around 400 rpm and when put into gear chugs and dies every time. Manual says that if all adj orrect and you want to increase idle speed to decrease timing. Well if I unhook the cam linkage and unhook the throttle cable Start engine and with a timing light hooked up engine needs to be around 10-12 ATDC and has good idle and smooth running. Not sure if I have enough adjustment in screw to achieve this much timing? Only other thing that has been done is the VRO stopped pumping oil so some one just plugged the oil line to pump and is still allowing pump to pump fuel only. Also dont know if this is any thing or not, I can not keep the fuel bulb hard while running. Dont know if this is separate problem or actually has something to do with the idle problem I am having. Oh one more thing if I trim motor all way up engine rpm increases by 2-300rpm, if I lower all way down engine will actually die after a couple of min. Some thing to do with back pressure in exhaust??
Any help to steer me in the right direction would be appreciated.
PS Engine is a 1996 J70TLEC
Fred
 
Bulbs do NOT STAY HARD once motor is running !-----Visit the shop and have them set-up the motor.---------Idle timing is a much misunderstood thing .-----Sorry, if you are not 100% sure on idle timing then make no adjustments there !
 
Thanks for the response but dont have a lot of faith in our local shop. They have tried twice to fix problem and can not. My big question is why does engine idle vary by 2-300 rpm when trimming from all way up to all way down. To me this sounds like a timing issue? Like I said if I unhook the throttle linkage and leave the throttles at the closed position and then unhook the throttle cable I can actually adjust the timing so engine purrs like a kitten but according to my light has to be around 10 ATDC?
Any thouhgts
 
You should NOT be adjusting timing at idle !-----------Only set the maximum timing advance.-----Believe it or not idle timing is a linkage adjustment and throttles open at the numbers specified in the manual.------What did the rebuild involve on this motor ?---New pistons and rings ?---------Working on a 1996 motor like that now.--------Shop refused to work on it and gave owner my number.----Needs one cylinder bored and one new standard piston.
 
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