(note: I've used the SEARCH function and read thru all 57 responses for "engine tuner"! The questions below are those I could not find answers for.)<br /><br />I am somewhat hesitantly looking forward to my first de-carb on my first engine on my first boat. A lot of questions were answered by browsing thru previous posts here but some doubts remain. I have a pre-owned Evinrude 90hp, 1997, V4, 1632cc in (what seems to be) excellent running condition.<br /><br />The plugs show some carbon deposit but nothing serious based on images I have seen on the internet and compared to my service manual reference images. I am thus assuming that a straightforward de-carb is a good way to go as opposed to a complete strip-down of the fuel system.<br /><br />I plan to use OMC Engine Tuner as recommended thru the electric primer valve. My boat is parked at a marina (on land). I have never done this before.<br /><br /> Treatment Questions <br /><br />1. Is there a special oil ratio for de-carbing? Some posts here suggested 50:1. Should I go for 25:1?<br /><br />2. After the treatment is complete, the manual suggests turning the engine OFF and waiting 15 minutes before re-starting and operating above 1/2 throttle for 3-5 minutes. In your experience, how long should I wait? <br /><br />3. Assuming the pistons are only lightly fouled, do I need to spray the Tuner directly into the cylinders with the plugs removed?<br /><br />4. Some posts here mentioned that the Tuner should not be allowed to stay in the engine too long. Should I do a couple of WOT runs before calling it a day? <br /><br /> Safety Concerns <br /><br />1. I am hesitant to perform the procedure in close proximity to the other boats parked adjacent to mine. Should the **** hit the fan, I would like to restrict fire damage to my own boat only. Hence, is it better to tie-up in the water (as the Seloc manual suggests) or can I get away by doing it on land? <br /><br />2. Similarly, I do not have access to a test tank. The manual mentions possible engine damage should the idle rate increase dramatically with no load on the shaft. Should this be a real concern? Is it better to do this in the water with the prop on? <br /><br />3. Do I need to buy a fire extinguisher for this procedure? Just in case...<br /><br />4. Near my marina there is a small body of water in between two bridges and surrounded by land mass. Water traffic is light. And there's plenty of space for WOT after the tuner treatment (as the posts here suggest). Should I conduct the procedure there? Rather than tied-up at a berth at the marina? <br /><br />As I'm sure you can gather, my main concerns are:<br /><br />1. The situation getting out of control (fire, explosion etc.)<br /><br />2. The engine dying out completely after/during the treatment and refusing to re-start thus stranding me in open water.<br /><br />3. The engine suffering damage due to no load on shaft.<br /><br />Because of #1 I am loth to attempt this close to other boats. Becuase of #2 I am hesitant to try this on the water. Because of #3, I think a water-based scenario is better.<br /><br />I realise some of my fears may be completely unfounded but I'd rather ask and look ignorant than screw it up and look stupid ; ) The collective wisdom and experience in these forums should prevent any major disasters.<br /><br />Thanks in advance and apologies for the looooong post.<br /><br />PS. I intend to change the plugs after the treatment as the posts here suggest.
<br /><br />Good Luck on the motor