So I have a 1988 3cyl 70HP Merc on a 14.5' fibreglass Fleetline. The boat was taken off trailer over winter for a trailer rebuild, and was running perfect last time it was in the water. After about 3 months of storage we got it back on the trailer filled with fresh fuel and took it to the water. As soon as I pulled away from the dock it seemed slow but did a few mins of cruising to warm it up before trying more throttle.
At full throttle it hits 18km/h, where it would normally get around 55-58km/h. At one point while doing laps it started to get a bit better, up to 30 km/h, but once we stopped and took off again it was back to slow again. The tach hasn't worked for years, but we believe it's the tack itself as the charging circuit is still working fine and it had a new rectifier last summer. My first thought was a fuel blockage or gummed up carbs but after around 10 minutes of motoring at "full throttle" it had used approx 8 liters of gas, a lot more than usual!
I've checked plugs, they are fine, stripped fuel pump and that seems fine. All the research I've done seems to point to a timing issue but I cant' see how that would change suddenly with the boat not being used. It's a pain as it starts and idles fine, revs fine in neutral so the only way to know anything we try has worked is to tow it to the lake and test.
At full throttle it hits 18km/h, where it would normally get around 55-58km/h. At one point while doing laps it started to get a bit better, up to 30 km/h, but once we stopped and took off again it was back to slow again. The tach hasn't worked for years, but we believe it's the tack itself as the charging circuit is still working fine and it had a new rectifier last summer. My first thought was a fuel blockage or gummed up carbs but after around 10 minutes of motoring at "full throttle" it had used approx 8 liters of gas, a lot more than usual!
I've checked plugs, they are fine, stripped fuel pump and that seems fine. All the research I've done seems to point to a timing issue but I cant' see how that would change suddenly with the boat not being used. It's a pain as it starts and idles fine, revs fine in neutral so the only way to know anything we try has worked is to tow it to the lake and test.
