84 25hp evinrude problem.

I got a 84 25hp Evinrude that sneezes at idle. It use to do it every once and awhile just at idle. Its gotten worse to the point it wont hardly idle. I have cleaned the carb 3 times. First time was soaked in carb cleaner with the plugs out and I ran tip cleaners thru every passage and sprayed carb cleaner and air thru them. 2nd and 3rd was with carb cleaner and air. New kit with float. Its running lean. The top plug is wet and bottom one is dry. Is the bottom crank seal leaking air? Thats the only thing I can think of causing this. I have replaced every rubber line on it. Tried different spark plugs. changed the coils from top to bottom and still wet plug on top and dry on bottom. If you put your hand over half of the intake on the carb it runs better but not great. Anyone got any ideas? I think its the bottom seal leaking air.

Thanks
Steve

I dont feel it pop back thru the carb. I havent seen it leaking around the crank case halves or noticed and around the intake bypass covers. the fuel pump is on top cylinder bypass cover. i thought it might been leaking and making the top cylinder run rich and thats why the plug is wet but i dont think its leaking. it runs great just idle it sneezes bad. I have the powerhead off now to look at the bottom seal. it appears to be a single lip seal and the new ones are double lip?

Thanks
Steve

I changed the seal and the hose that came from the top bearing to the bottom bearing. No other signs of leaks anywhere. Still does it just not as bad. I am out of ideas. Any suggestions????

Thanks
Steve

compression is 120 top and bottom cylinders. carb is closed at idle. i looked in the bore today and double checked it. I took a look at the service manual on boatinfo.no to check the sync of the carb. In the manual is says to use "B" location. the throttle shaft should start to move when the roller is to the starboard side of the mark. Ok Which mark??? theres 2. I guess the first one. So thats where i set it. It ran better but still acted up. So i thought what the hell lets got to the port side of the mark. Ran even better but still sneezed every once and awhile and died. Still have alot of turns on the idle screw out. 3 or 4 out from the seat. I looked into the timing and according to the manual its set at wot in forward gear at 30 degrees. So no timing adjustment at idle, i guess?? Theres what I did to it today.

Steve

I pulled the carb off today. looked at the reed valves. I took a oring pick and lightly opened each one just a bit to make sure none was stuck. Everything looked good in the intake. I tore the carb back apart. The idle circuit is fed by a brass tube that runs up the middle of the carb and is inside the high speed tube. I ran a piece of wire up the idle pickup tube with the idle needle out to make sure it was clear. and it was. when i rebuilt the carb the first time. every gasket was replaced and the plugs taken out and soaked in good quality carb cleaner overnight. I installed the red needle gasket the first time it was rebuilt along with the nozzle well gasket. I never got a chance to start it.

Steve

Ok I marked TDC for both cylinders. put in the test tank. idle jet set to a round and 1/4 out. synced to the starboard side of first mark as manual says. Hit start button and fired right off. Adjusted idle jet. Ended up about a round and 3/4 out. checked timing with the marks. when it sneezed it was still in time on both cylinders. But now where its set at it idles like it should and dont sneeze and runs. Next test will to be run on the lake. I have no idea on what made it change. Unless the red packing on the needle wasnt seated good. I did bump up the float level a tick but I wouldnt have thought it make a difference in that. Running it on the lake will be the real test. It set and ran at idle for a good 30 min. I would open it up and let it run for a few seconds then back to idle. No sneeze.

Steve

Well I ran it on the lake today. Still does it just not as bad. I will be idling along and sneeze. It might go awhile and do it one or three or four times and die. Seems worse after you have it opened up going across the lake then back it down to idle. Which I figured it would be when it would do it the worst. I am at wits end with this thing. I didnt see any signs of leakage around the crankcase or the intake bypass covers.

Steve

I did turn it out about a half round it made it better but still did it every once and awhile. esp when you came from WOT to idle. if you slowly came from WOT to idle it wasnt as bad. Just still something not right. I will try and run it in the tank tonight and adjust it out some more.

Steve