Hope this is the right forum. I'm new to the forum so bare with me. I'll give as much detail as I can and if you need something else let me know. I live in NE Ohio. I have a 20 ft Larson with a 4.3 merc 175 HP. I only ran my boat twice last year and didn't notice it running badly but wasn't tip top. This year when I ran it the first time it would barely plane out and was really sluggish getting out of the hole. Once on plane the boat would run 30 MPH (GPS) and 3800-4000 max RPM (Trimmed fully) The first thing I did was tune it up. I have replaced the following already this year: Spark Plugs, Spark Plug Wires, Dist Cap, Rotor, Fuel Filter, Prop, and Alternator. I was running a 3 blade 13.75 X 21 prop but switched to a 14 X 20 4 blade (I wanted to get a quicker hole shot). The next time out it ran better but still sluggish out of the hole and still only ran max 4000 RPMs at WOT. I took it to the shop and had the timing checked (I don't have a timing light nor have adjusted it before. I am a little handy but have limits). It was off 8 deg. Next time out boat ran great. Boat ran 40 mph at 4300-4400 RPM and fully trimmed 45-46 MPH and 4800 RPMs at WOT (which is where I think it should be by seeing other posts). Life was good it was the beg of the season and the boat was running great. Next time out the boat got out of the hole shot good but not as good as right after I had the timing fixed. Once the boat planned out it was running 33 MPH at 3800 RPMs and 35 MPH but never went over 4000 RPMS at WOT (via GPS). I also now have a slight miss/hesitation in low speeds and in higher speeds. It is not consistent just every once in a while. I called the shop and he thought it may be a Module (which I think is rare but could be a possibility) but before I go spending the money for that I wanted to see what you guys thought. My thoughts are the Coil (but don't know if that effects my problem), Fuel Separator (If mine has one lol see that on another post) anti siphon valve. The boat seems to run pretty smooth now but just not where it was right after I had the timing adjusted. (Oh almost forgot) I had the timing rechecked today and the shop indicated it was the same as they set it. All thoughts and comments are much appreciated.
