motor bogging

[dieselcat]

1992 70 hp johnson.
motor starts and idles like a champ but at any throttle position past idle motor bogs down.fast idle it will rev up fine.any ideas?

 

[Joe Reeves]

Re: motor bogging

You've described an engine with one of three possible problems...........

1 - Fouled carburetor (Remove, dismantle, clean & rebuild).

2 - Throttle butterflies opening too soon (Before the scribe mark on cam is aligned dead center with the throttle roller).

3 - Sticking timer base under flywheel (retarded timing condition).

It is normally the carburetor(s).

 

[dieselcat]

Re: motor bogging

Just finished taking apart and cleaning carbs took out to try and same problem,still bogging.i did take cover off and watch trigger/timer base and it doesn't appear to be advancing I dont see anything moving accept the throttle. I did put a new stator and powerpack on the motor...

 

[Joe Reeves]

Re: motor bogging

Just finished taking apart and cleaning carbs took out to try and same problem,still bogging.i did take cover off and watch trigger/timer base and it doesn't appear to be advancing I dont see anything moving accept the throttle. I did put a new stator and powerpack on the motor...

Doesn't appear to be moving? Check the timer base out with the engine NOT running. Hood off, have someone slowly advance the throttle while you observe the timer base. It must move towards the full spark advance stop screw way before the carburetor butterflies start to open.

Do you have compression and spark on all cylinders?

 

[dieselcat]

Re: motor bogging

When I give boat WOT the trigger does not move no matter if motor is running or not.i checked that b4 I cleaned carbs.motor compression is 98 95 98 and yes I am getting spark.
not sure if you saw my post about the trigger and where I had ran a tap into trigger about an 1/8" while I was cleaning the threads out on flywheel so that I could get bolt in for the puller to change stator.i had no idea the bolt hole went all the way through,my 90 hp does not so I assumed this one didnt either.

 

[dieselcat]

Re: motor bogging

Ttt

 

[dieselcat]

Re: motor bogging

Ended up taking motor to my local dealer hopefully its just the timing in need of adjustment. Will post results when I get boat & motor back.