Carbs flooding terribly

[cgeiger032989]

Hi,
Let me start by saying I've learned a lot here so far. This is my first post.

So, I took my 1998 Nitro 700LX with a 1998 force 120 hp out and has no power under load. Got back home and noticed the bottom carb flooding out the front and side (vent?). Took it off and cleaned it, it had trash in bowl. Looked up about the float height and adjusted as needed (in accordance with

http://forums.iboats.com/forum/engi...ards/660715-98-mercury-force-120-carb-leaking ).

Because of the amount of trash I went ahead and pulled the top carb and repeated my actions. Now both carbs and flooding badly. What should I do now? Thanks in advance!

 

[Scott Danforth]

I would get carb kits and new floats

 

[pnwboat]

If you are experiencing lack of power, the first thing you should check is compression. Your readings should not vary more that 10% from the cylinder with the highest to the cylinder with the lowest reading.

Most of the needle vales used in the carburetors in the later 1990 4 cylinder motors have a rubber tip. Could be that the rubber tip has deteriorated to the point that it doesn't seal properly. Could be some debris caught in the needle valve seat. Float height is set too high, that is, when inverted, the end of the float opposite the pivot point is too close to the carburetor body.

I would double check the float level, since the top carburetor wasn't leaking before you adjusted the float level. Try setting the float level so that the end of the float is just a tad farther away from the carburetor body....maybe like 1/32nd of an inch farther than before. May take a couple of attempts to get them to seal.

Just wanted to add, that if you don't already have one, you should install an in-line fuel filter between the fuel pump and carburetor.

 

[cgeiger032989]

I will try this tonight. And there is a filter inline. Thanks

 

[jerryjerry05]

The "level" of the float is way more important than the drop.
The carb upside down and level
The float should be even with the base.
​When you cleaned the the carbs.
I wash them with Dawn detergent and rinse in clean water.
Then blow dry .Add nothing just mount clean and dry.
Any cleaners or WD can make the needle valve stick.

​Fuel coming from the carb could be bad reeds too???

When the carbs off inspect the reeds, any broken or excessively gapped reeds can allow fuel to come out the front.
​Someone mentioned a compression test. Good idea.
Do a spark test too.
Inspect the plugs.

 

[gm280]

I would start with carb kits myself like Scott stated above. And make sure you get new needles and seats if you can. JMHO!

 

[jerryjerry05]

New carb kits?
​They can come with parts that don't fit.
Floats that don't adjust.
IF?? there is no corrosion or excessive crud build up.
Just a good cleaning is all you need.
Most carbs just need a cleaning.
You can buy the kits but your old stuff might not come apart??
Some have pressed in seats.
Some come with rubber tipped needles and some have solid needles and the kits might have shorter needles??

I'm just saying be careful with replacement parts and compare them.