Indmar assault 310 issues

[fu-man]

2003 outback with the 310 carb engine new to me last fall.

1. Never starts with the turn of the key even when warmed up. Always have to give it throttle to start.

2. Even after adjusting idle screw can't find (and maintain) the sweet spot between low idle 650ish rpm where it dies and 900 rpm hard shifting. Yesterday morning she idled around 700-750ish and was fine. Then I ran her on the lake 3500+ rpm. After that the idle jumped up to 900-950 rpm (without adjusting the screw). Then in the afternoon the idle rpm was back down to 650-600 and struggling to run.

3. I have had occational hard running at high rpm (3000 plus) when the trans is engaged. However the problem has not happened ar high rpm in neutral. I get hesitation, bogging down, a loud clap noise "Kah" (backfire/misfire?), and the engine will suddenly die at 3200ish rpm. This has happened twice but the issue has resolved itself. Had it running 3800 rpm yesterday with no problem.

At first I thought 1 and 2 were carb issues and that 3 was a fuel pump or spark plug issue. However, a little research and a conversation with a friend (who has the same engine) has suggested that it may be a bad distributor cap. Thoughts?

[ranger098]

2003 outback with the 310 carb engine new to me last fall.

1. Never starts with the turn of the key even when warmed up. Always have to give it throttle to start.

2. Even after adjusting idle screw can't find (and maintain) the sweet spot between low idle 650ish rpm where it dies and 900 rpm hard shifting. Yesterday morning she idled around 700-750ish and was fine. Then I ran her on the lake 3500+ rpm. After that the idle jumped up to 900-950 rpm (without adjusting the screw). Then in the afternoon the idle rpm was back down to 650-600 and struggling to run.

3. I have had occational hard running at high rpm (3000 plus) when the trans is engaged. However the problem has not happened ar high rpm in neutral. I get hesitation, bogging down, a loud clap noise "Kah" (backfire/misfire?), and the engine will suddenly die at 3200ish rpm. This has happened twice but the issue has resolved itself. Had it running 3800 rpm yesterday with no problem.

At first I thought 1 and 2 were carb issues and that 3 was a fuel pump or spark plug issue. However, a little research and a conversation with a friend (who has the same engine) has suggested that it may be a bad distributor cap. Thoughts?

That all kinda sucks. Sounds like you either have a dirty carb... or maybe just need a tune up (new dist. cap, plugs and wires). Typically electrical issues are present when you only notice the issue with the engine under load, and its fine in neutral. My engine (exact same as yours) sometimes needs gas to start when warm, sometimes doesnt. Its safe to call that normal though on a carbd engine. Long as it starts, i dont mind giving it a little blip. Just my .02... good luck.