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finding tdc on 2000 70hp jhonson

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outback32

Regular Contributor
So I have a manual and a piston stop tool. According to the manual go 1.5 inches past the cast t in the flywheel. Make a mark screw in tool until it contacts the piston. make a mark continue turning flywheel until it contacts the piston again. if the piston is against the stop tool how are you supposed to turn it. ive tried I have no idea what im doing wrong. does it have to be a omc tool or will any stop tool work.
 
thats what i thought to my manual says clockwise for both. I even found a YouTube video put out by omc and it even says in the video clockwise thats why I was wondering how it was supposed to work. Another question my flywheel has 1 set of timing marks a blank space followed by another set of identical marks. do i use the first set of marks for this procedure
 
im following the directions step by step in the the link and synch. My manual starts at finding tdc thats why im doing this. So scott should I go counterclockwise or move stop tool out and go clockwise.
 
what about the timing marks on the flywheel do I start at the first set of marks. it has a set of marks then a blank space and another set of identical marks. thanks for the help
 
At one time i made my own stop tool ,screw it in then turn the motor clockwise until the piston stops against the stop tool ,then make a mark on the outer edge of the flywheel .Then turn the flywheel anti clock wise untill the piston stops against the stop tool ,then make another mark on the outer edge .now you have 2 marks on the flywheel then you have to bisect that angle working from the center .between the 2 marks is your TDC i did this because there was no tdc mark on the flywheel nor a pointer on the block i made my own pointer and determined the tdc.
 
So I have a manual and a piston stop tool. According to the manual go 1.5 inches past the cast t in the flywheel. Make a mark screw in tool until it contacts the piston. make a mark continue turning flywheel until it contacts the piston again. if the piston is against the stop tool how are you supposed to turn it. ive tried I have no idea what im doing wrong. does it have to be a omc tool or will any stop tool work.​
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That is the correct way to do it..the piston is on the downstroke when you screw in stop, then when continued rotated clockwise the piston will hit stop on up stroke
 
If you have a Dial gauge tool its better then you don,t have to turn clock wise and anti clock wise as the piston comes up it will push the dial gauge in, and when the piston goes down the dial gauge will come out then you can determine the TDC from the readings on the dial gauge.
 
I have another question in my manual it says to hold the flywheel and loosen the pointer screw and move the pointer to the cast t spot. my timer pointer is mounted to the bracket in front of the flywheel. the pointer doesnt move in a bracket its stationary. so im not sure what to do about that
 
If the pointer does have a slot in it where the screw goes in and if some one has never fiddle with it and moved it then take it for granted that that,s where the factory put it and leave it there k .then turn the flywheel until the no 1 piston is at the top and the T mark lines up with the pointer .take the plug out to confirm by feeling with a screw driver whether the piston is at the top. if some has moved the pointer in the slot ,then you have to use your piston stop tool and make new marks on the flywheel and cannot use the original T.
 
Ok thank you the only thing i know for sure thats been done is the flywheel qas removed last year to replace the timer base. would that affect timing or tdc
 
No it would NOT -----But if the flywheel nut was not torqued properly the key could be sheared and that does throw out the timing !!!
 
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