I bought this boat a month ago and have been working on it. It runs great on top but it bogs/sputters from the low thru the low mid when I nail the throttle from idle. It's worse if it's been idling for awhile (2-3 minutes...) but it still does it even if I come off a full throttle run, stop and them nail it. 140 compression on all 3. All fuel lines replaced. New gaskets in fuel pump. In line filter.
I rebuilt the carbs with OEM kits. Soaked them for several hours in Berryman carb cleaner. Blew out etc...
I bought the OEM manual for this exact motor thru Ken Cook.
I've linked & synced the thing perfectly as far as I can tell, I've even played with the timing as well outside of what is recommended. Still the bog. I'm a pretty good mechanic, I've ridden and raced 2-stroke bikes and quads for years and now 4-strokes so I'm pretty capable. However, I've never worked on a boat motor not to mention a 3-cylinder till now.
The plugs are burning medium brown so I don't see a overly rich or lean condition but I'm probably seeing the burn off the main jet not so much of the low speed or mid jet.
I've searched for hours and just keep seeing this or that.... Blah blah....
From my 2-stroke experience, It seems to me to be "loading-up" off the bottom. When I nail it and it finally cleans out and goes, there's a bit of a cloud of smoke back in the distance behind the wake. To me that suggests a rich condition.
I've read some threads hear talking about the bog being a lean condition but from my experience that doesn't seem to be the case. I've read about carb shafts being worn and I've had that with other motors but doesn't seem to be the case with the carbs on this motor. It's a really solid motor and everything functions perfectly but the bog off the bottom is unacceptable to me.
Many people on this forum post this and the other thing but never post actual jet sizes so I have nothing to go off of.
However, I will actually post some useful information with jet sizes and maybe someone with REAL knowledge can tell me if these are off.
I'm not sure what these numbers (letters) refer to, whether it be, thousandths or what but hopefully someone can chime in.
Main - 52D
Off idle - 35
Idle - 57
I'm in Phoenix, AZ and the lake I've been testing at is 1,500 ft above sea level.
To sum it up I think the bog is due to the bottom jetting being too rich but I could be very wrong. I know very little about these carburetors but they seem very basic. What the dynamics are, I don't know. Jetting was/is everything in all the 2 & 4-stroke motors I've ever worked on in terms of powerband etc, but I see very little written about jetting on these motors. It's mostly, "link and sync", or "your carbs aren't clean", etc...... I don't know...
I've also searched around briefly to find where to get different jets/sizes and have found nothing. Johnson dealer only? Are they even available?
All help will be much appreciated! Thank you in advance.
I rebuilt the carbs with OEM kits. Soaked them for several hours in Berryman carb cleaner. Blew out etc...
I bought the OEM manual for this exact motor thru Ken Cook.
I've linked & synced the thing perfectly as far as I can tell, I've even played with the timing as well outside of what is recommended. Still the bog. I'm a pretty good mechanic, I've ridden and raced 2-stroke bikes and quads for years and now 4-strokes so I'm pretty capable. However, I've never worked on a boat motor not to mention a 3-cylinder till now.
The plugs are burning medium brown so I don't see a overly rich or lean condition but I'm probably seeing the burn off the main jet not so much of the low speed or mid jet.
I've searched for hours and just keep seeing this or that.... Blah blah....
From my 2-stroke experience, It seems to me to be "loading-up" off the bottom. When I nail it and it finally cleans out and goes, there's a bit of a cloud of smoke back in the distance behind the wake. To me that suggests a rich condition.
I've read some threads hear talking about the bog being a lean condition but from my experience that doesn't seem to be the case. I've read about carb shafts being worn and I've had that with other motors but doesn't seem to be the case with the carbs on this motor. It's a really solid motor and everything functions perfectly but the bog off the bottom is unacceptable to me.
Many people on this forum post this and the other thing but never post actual jet sizes so I have nothing to go off of.
However, I will actually post some useful information with jet sizes and maybe someone with REAL knowledge can tell me if these are off.
I'm not sure what these numbers (letters) refer to, whether it be, thousandths or what but hopefully someone can chime in.
Main - 52D
Off idle - 35
Idle - 57
I'm in Phoenix, AZ and the lake I've been testing at is 1,500 ft above sea level.
To sum it up I think the bog is due to the bottom jetting being too rich but I could be very wrong. I know very little about these carburetors but they seem very basic. What the dynamics are, I don't know. Jetting was/is everything in all the 2 & 4-stroke motors I've ever worked on in terms of powerband etc, but I see very little written about jetting on these motors. It's mostly, "link and sync", or "your carbs aren't clean", etc...... I don't know...
I've also searched around briefly to find where to get different jets/sizes and have found nothing. Johnson dealer only? Are they even available?
All help will be much appreciated! Thank you in advance.