Rough Running w/ Dual Carbs, And now low fuel pressure too. Options

[Craigers17]

So I've been trying to track down a rough running issue with my 2056 w/ dual 40IDF's. It has not been running well for several months, and has had spells of sitting for a while. When these issues started, probably 9 months ago now, I changed out the old fuel filter and relocated the pump and filter to the front and upgraded both to the type that Tangerine sells. I also took that opportunity to install a stainless steel line and all new rubber lines. (the problem existed BEFORE I did all of this)

Recently, in the last week or so, I replaced both manifold and carb gaskets. I haven't actually opened up the carbs yet, but have cleaned all the jets. After this work, I had it running great for about a quarter mile, and then started backfiring and bogging down. I have a fuel gauge and also noticed that it is now only reading about 1.25 to 1.5. It normallly sits around 3 consistently. I suspected maybe I had a fuel line that was kinked under the tank, so I pulled it and they are fine with no leaks.

I am thinking that the fuel filter may be clogged after having sat dormant for so long, OR, I might have some clogging going on in either my fuel "T" splitting the carbs or in the "T" that contains the gauge. My only other guess is that something is going on with the floats. I know this post is a lot, but if anyone has any ideas, please feel free to chime in. Thanks!

[Superhawk996]

There is no magic that accounts for the change in behavior.

Moisture doesn’t just disappear on its own - especially if it’s bound to ethanol. Water sinks to bottom of tank and can’t evaporate because it’s not exposed to atmosphere.

Like you said, your main fuel filter may have been partially blocked and changing that helped.

I know you cleaned carb jets but did you clean the inlet strainers that are in each carb? This can impair fuel flow. And of course there is the sock in the tank - make sure that isn’t blocked up. Over time, just sitting debris that was plugging these screens can settle, reopening them to flow until they have a lot of flow and the debris gets picked back up again re-blocking the filter screens.

Likewise, get that linkage issue sorted - you can buy new lever arms if a hole has become too elongated. Unsynchronized linkage will cause roughness.

[Craigers17]

There is no magic that accounts for the change in behavior.

Moisture doesn’t just disappear on its own - especially if it’s bound to ethanol. Water sinks to bottom of tank and can’t evaporate because it’s not exposed to atmosphere.

Like you said, your main fuel filter may have been partially blocked and changing that helped.

I know you cleaned carb jets but did you clean the inlet strainers that are in each carb? This can impair fuel flow. And of course there is the sock in the tank - make sure that isn’t blocked up. Over time, just sitting debris that was plugging these screens can settle, reopening them to flow until they have a lot of flow and the debris gets picked back up again re-blocking the filter screens.

Likewise, get that linkage issue sorted - you can buy new lever arms if a hole has become too elongated. Unsynchronized linkage will cause roughness.

Thanks for the reply. I'm fairly sure it's not a flow issue from tank or pump(at least not any more). At one point in my troubleshooting I removed the main fuel supply line from the "t" and set it into an empty gallon container...then turned on the pump....it was flowing freely. Also the tank and sock have probably less than 100 miles on them. I did remove and clean the inlet strainers as well.

Another thing I did today was cut the old filter open with a sawzall. I have attached a couple pics of "the innards". I'm no expert on fuel filter autopsies, but, to me, it looked pretty clean.....as if "crud" coming from the tank wasn't the probable issue... which stands to reason as the tank is almost brand new.(although the cross section piece in pic #3 might be a little suspect??)

For now, I'm going to replace the worn throttle lever(not sure I'm using the right terminology, but I've attached a pic) and finish tuning the carbs again.....this time using very small increments on each adjustment.

Fuel Filter Autopsy Pics:







Throttle lever replacements parts: