Re: Dentonation / spark plug choice Evinrude 1989 90HP VRO
Thanks for the quick answers, everyone.<br /><br />Dhadley, the mechanic was a "garage shop" that was recommended to me by a local marina that said they wouldn't be able to get to my boat for almost 3 months. I don't know what he set the timing to, but I know that the airflow cover has a label that says that TDC is 28 degrees. I haven't checked it with my own timing light, but then again, I was having trouble setting the timing myself, which is why I wanted someone to look at it.<br /><br />Here's a little history: The engine always ran rough in idle and would stall out if idling for more than a few minutes once it warmed up. During the middle of the season last year, it started hesitating or dying out once you gave it throttle (like pulling up a slalom skier, for instance). Using my manual, I tried to check the timing and linkage with the boat on the trailer but in the water at a little-used launch ramp near my house. The problem didn't go away, and a week later my tell-tale started running weak, so I figured that since I needed to have the water pump replaced, I might as well have someone look over the linkage and timing. When I brought it to the mechanic, he asked when the last time the carbs were rebuilt. I had bought the engine used in 1998, rebuilt it in 2000 (wrist pin retaining ring gave way and the pin scored the chamber something fierce) but had not rebuilt the carbs with a kit during that rebuild; I had only replaced the gaskets. He suggested that I have the carbs rebuilt while he was doing everything else, and I gave him the go-ahead on that. He pulled a plug, noticed that it was the surface-gap plug that my manual said was the right one for "sustained, high rpm use" and said that he had a different Champion plug that he used for these engines that would give me a little better performance. I told him to go ahead and swap the plugs.<br /><br />When I got the boat back, it started right up, idled strong (albeit at 1100-1200 rmp instead of the 850 that it did before) and didn't hesitate at all when dropping down the throttle. I tested it out for a little over an hour, and pulled it from the water, satisfied that my camping weekend was saved.<br /><br />Three days later, we took it down to the Illinois River, loaded in our camping gear, and about 5 min down river, I opened up the throttle, and it climbed up to 4300 RPM, then puttered out to about 2000 for a minute, then died completely. As I put in my earlier post, I checked compression on the river, found that #3 was shot, and limped it back to the dock by holding the carbs open as my friend steered.<br /><br />2 bores at .020 over and a gasket kit later, it's back up and running with the surface-gap plugs, but still idling at 1200.
