1985 DT 55 low RPM under load

joe brewer

Cadet
Joined
Jan 15, 2014
Messages
25
Hello everyone I'm having issues with my 1985 suzuki DT 55. I have rebuilt the carbs, fuel pump, water pump, fuel line and primer. 120 psi on alk cylinders. The engine runs perfect at idle throttles up perfect at idle revs perfect in neutral does not miss or sputter. When I put it in the lake under a load I get low rpm guessing around 2k at WOT. 1 thing I have not done is new plugs. All carbs have fuel in the bowls. No alarms going off what so ever. I noticed my air fuel screw seemed to be turned very lean. Could this be my problem? What I don't get is that under a load it runs very smooth just no power. What am I missing?? Any help is appreciated thanks!
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,228
enough fuel is needed to produce power.
no power is needed without a load.
have you checked to se if the alarm system works?
 

joe brewer

Cadet
Joined
Jan 15, 2014
Messages
25
I unhooked the middle cylinder and top cylinder oil injection line and there was none that came out. Should there be oik coming out of the lines as soon as it is unhooked or is there not alot of pressure in those lines?
 

joe brewer

Cadet
Joined
Jan 15, 2014
Messages
25
Ok I tried to adjust the air fuel mixture screws on the carbs took it out today and had intermittent power. Bottom plug was oily the top 2 cylinders looked good
 

joe brewer

Cadet
Joined
Jan 15, 2014
Messages
25
How do I check the alarm system? I suspect the issue lies in there somewhere. I pulled the oil level sensor out of the tank and ran it. No alarm went off
 

eddie haskell

Petty Officer 3rd Class
Joined
Apr 5, 2015
Messages
87
Have you done a compression check?
If your rings are worn you won't produce enough compression to get er done......
To continue to run a low comp motor can lead to major failure.
 
Top