1983 Suzuki DT 25 running rich

[rdm924]

Hi Guys, I have a 1983 DT 25 which is running rich and lacks power under load, I have cleaned the carb, replaced the float, needle and seat, checked the fuel pump for leak into the crankcase, replaced plugs, have about 120 psi compression and spark at idle and under load. continues to blacken the plugs. don't know what to check next and need some help

Thanks for any help

Richard

 

[deejaycee_2000]

Re: 1983 Suzuki DT 25 running rich

The ideal carb setting is 1 & 1/2 full turns outwards from soft stop .... is the carbs synced properly? What pitch prop you running?

 

[rdm924]

Re: 1983 Suzuki DT 25 running rich

the old girl only has one carb and I have tried 1 1/2, 1, and 2 turns on the mixture screw, I,m not sure on the pitch but she had lots of power for the boat, then something changed, it lost power and started running very rich.

 

[robert graham]

Re: 1983 Suzuki DT 25 running rich

If your fuel is old or contaminated it can foul plugs like that. Motor has a manual choke? How is your thermostat and is motor reaching normal operating temperature? If motor never gets warmed up to normal temperature it can foul plugs. Good Luck!

 

[rdm924]

Re: 1983 Suzuki DT 25 running rich

yeah fresh fuel and manual choke, I will check the operating temp, what is an ideal temperature? just an idea, could the exhaust be restricted causing it to run rich?

 

[99yam40]

Re: 1983 Suzuki DT 25 running rich

restricted exhaust will cause running problems but not sure if it would be running rich.
If it cannot push the burnt fuel and air out it will have problems sucking in air it needs also.
The air flow in through the carbs determines the fuel/air ratio.
I have seen 2 stroke weed eaters and blowers with their exhausts restricted by carbon to the point of not being able to get their RPM up much past 1/2 throttle.