Hi,<br />I have an Evinrude 35 hp (3-cyl.) year 1998 or -99. It has been running great except that the ignition control box has been changed once after 6 months of use.<br /><br />All the troubles started out this summer: I've done some fishing earlier at low speed, no smoke, great idle. But this summer thick smoke has been following the boat at idle speed. First, I thought that oil mixing pump has to be broken (I checked the spark plugs, etc. before that). I replaced the pump with a used one, (from a well running, nearly new motor), but there was still the smoke! I checked the compression of the cylinders and the fuel pumps, OK. Additionally, I checked the ignition by detaching the spark plug wires, and the motor ran with all cylinders (also every cylinder separately). However, removing the spark plug wires of the two upper cylinders had less influence on idle than the lowest one. Since the replacment of the oil pump did not work, I had to take the boat to the mechanic. At his point, I thought that the reason might be the ignition box missing some fire for the upper two cylinders. Gas drops coming out of exhaust every 4-5 seconds also indicated that the motor gets too much gas in addition with oil. It has to be stated that the motor has been running great at high speed, only the idle is the problem. The smoke starts to come out 3-4 minutes after slowing down to idle or to very low speed.<br /><br />I got my boat back from the mechanic about three weeks ago and the diagnosis was --- the oil mixing pump was broken. It was a bit difficult to believe that since the pump was from another motor, but, anyhow, they are the experts... Additionally, they said that the hoses of the fuel pumps were incorrectly installed, i.e. in wrong order (I had not changed them!). However, I was happy to get my boat back, but quite unhappy to pay 466 for the pump only.<br /><br />Now, you may ask why did I wrote here, since everything has been fixed. No, the smoke started to come out again a couple of days ago, after only 5 gallons of use. I have also tried to change the 2-stroke oil brand, but no help. Before I take my boat back to the mechanic, I want to ask if anybody has same kind of an experience. The oil pump just cannot be the reason. I'm still thinking that this could have something do with the ignition box. The strange thing is that the engine also seems to be consuming some extra oil, which doesn't quite fit the ignition fail. However, the fuel pumps are operated by the vacum hoses coming from the cam chamber(?), and the oil pump is operated by the fuel pressure and flow. I was thinking that the unburnt fuel in the cam chamber may cause some extra trouble for fuel pumps and fuel pressure and that may change the operation of the oil pump and the oil mixing ratio. So,please let me know, if you have any ideas for the possible causes.<br /><br />Many thanks in advance for your answers!<br /><br />Pasi/Finland
