2000 70hp bogging and then takes off runs fine on top end

[flatsider45]

I have a completly new fuel system,tank clean,all new hoses,primer bulb ,water seperator,carbs gone through,new cdi pack,new plugs.Cranks fine every time,will idle in gear until you start to put the fuel to it and thens boggs down.Can feather it under way at the carb linkage and get it to move a little better for a minute or three then all of a sudden it will snap out of it and run wot with no problem.Bring it back to idle and take off with no problem.Let it sit for a while say fishing a spot for an hour or two and go to move and it may take off just fine or not.Have to go back to the throttle linkage to get it to move at a little better speed and bam it takes off again just fine.motor has 135 lbs compression flat across all three cylinders.It's almost like you snap a switch when this happens.It is a systems check motor. No buzzers,no warnings no nothing,just does and then dont .Any ideas?

 

[DJ]

Re: 2000 70hp bogging and then takes off runs fine on top end

CLASSIC symptoms of "Sync. and link" being off. It's different for every engine, somwhat. So you need the repair manual. Perhaps someone has that exact same engine can chime in.

 

[boobie]

Re: 2000 70hp bogging and then takes off runs fine on top end

Have you checked the timer base under the flywheel to see if it's sticking??

 

[flatsider45]

Re: 2000 70hp bogging and then takes off runs fine on top end

No I haven't.Didn't think about it when I was back there on the linkage trying to get it to come up on the pad.I'll give it a look see.If it is sticking what lube is recommended? Thanks for the jog!

 

[boobie]

Re: 2000 70hp bogging and then takes off runs fine on top end

I would assume this is a 2 stroke Johnson. If it is sticking you use tcw 3 on the plastic ring on the timer base and molylube on the center bushing.

 

[flatsider45]

Re: 2000 70hp bogging and then takes off runs fine on top end

Thanks for the info.I'll give it a shot to see if it helps.This motor runs to good when it's acting right.The motor doesn't have but about 50 hrs on it.I did have the cdi go bad just sitting on the trailer.Someone told me that a battery going dead will reak havoc on the electronics on these motors,So I installed a battery switch on it to cut it off when not in use and when charging with the onboard charger.Don't know if thats what caused it but one day running fine and the next time approx. three weeks later dead as a hammer.I looked into the temp switch causing it to go into s.l.o.w. mode.It only has the one temp switch and I haven't removed it yet to do a heated check.I've checked all grounds and run it in the dark to see if I could find a gremlin spark somewhere on the motor,Nothing.