Couple questions for timing 70hp Johnson

[IRBFishin]

I've been struggling with this 1978 Johnson 70 for a couple of years now. PO said it sat outside a lot and he messed with the timing and never got it re-set correctly. I started with put a new water pump, new fuel pump but it kept stalling under a load. I rebuilt all three carbs and it made a world of difference. Can get on plane okay but still seems to sputter a little and I tried pulling a friend on a wakeboard (160lbs) and couldn't get him up to save my life.

I followed the manual on the carb rebuild and the link n synch and took it down to the water tonight with my timing light to see if that is my remaining problem. I'm aware of Mr. Reeves timing method but thought I would just take it to the launch and leave the boat on the trailer and time it at WOT.

When I hooked up the timing light to the number one cylinder and cranked the engine, it started fine but then the flywheel wasn't turning as the engine ran at idle. The timing light was flashing but without a flywheel turning I couldn't time it. Put it in gear and it died when I tried to throttle up. Took the timing light off the #1 cylinder and the flywheen turned just fine and seemed to run better at WOT.

What gives? Is it normal for the flywheel to stop spinning when timing light is hooked up? Could the timing be causing my sputtering or could it be the jets or something else? Sorry for the long post, I hope someone out there can help. Seems like lots of questions get asked but no solutions are posted when the problems are solved.

 

[tashasdaddy]

Re: Couple questions for timing 70hp Johnson

the motor could not run with out the flywheel turning. the strobe light flashes in the same place each time, making it look the the wheel is not turning.

use Joe Reeves method, much easier, and work just as well. 1978 70 hp timing WOT 17 BTDC, so with Joe's method, you are looking for 13 BTDC. just put a white mark on 13, and you can do it in the shade.

 

[IRBFishin]

Re: Couple questions for timing 70hp Johnson

Wow, I feel crazy, I swear that flywheel wasn't turning. I'll use Joe Reeves method now though. Anyone have a suggestion for where to get a spark gap tester to use with Joe's method?

Also, what does "set the timer base under the flywheel tight against the rubber stop on the end of the full spark timer advance stop screw" mean? When I push the throttle control to WOT the timer base moves forward and stops against the timing setting screw. Is this what he's talking about? Sorry for my ignorance I'm trying to do-it-myself for experience and saving money. Thanks.

 

[norville]

Re: Couple questions for timing 70hp Johnson

Wow, I feel crazy, I swear that flywheel wasn't turning. I'll use Joe Reeves method now though. Anyone have a suggestion for where to get a spark gap tester to use with Joe's method?

Also, what does "set the timer base under the flywheel tight against the rubber stop on the end of the full spark timer advance stop screw" mean? When I push the throttle control to WOT the timer base moves forward and stops against the timing setting screw. Is this what he's talking about? Sorry for my ignorance I'm trying to do-it-myself for experience and saving money. Thanks.

spark gap tester any auto parts store. it has a screw and makes the gap larger.. Less than $8.00

timing setting screw is what he's talking about so yes. I used red nail polish to mark my timing.

good luck, I'm going through the same thing.

bob

 

[IRBFishin]

Re: Couple questions for timing 70hp Johnson

Working on J.Reeves timing method today. Sorry but another question. To bypass the neutral safety switch at the controls, I disconnected the throttle cable to move the timer base and cam to WOT. I grounded #2 and #3 wires to the block. Should I manually move the gear selector to forward when checing timing even though the throttle lever remains in neutral at the controls? Thanks. I know I'm getting close...

D