Hi,
​​​​I'm trying to fix an engine issue with my '93 Scarab 38. The previous owner suspected the fuel pickup filters to be clogged.

Does anyone know how these things work on a mid 90's Scarab? (I unthreaded the fuel hose from one of the tanks, but that only left a short aluminum (?) adapter threaded into the tank. When removed, the adapter uncovered a straight hole (like the inside of a tube) going down to the bottom of the tank, but it didn't seem possible to remove it, since it looked as though it was part of the aluminum tank...)

Does anyone know how if there are filters in the tanks of these boats? What should be the first thing to look for when the engines seem to stall and die all the time?

(I have checked the fuel vent lines and they seem to be ok)

Any idea/experience from a similar boat/issue would be appreciated!

There is no filter in the tank does the fuel line have an anti siphon valve its a fitting with a ball and spring in it. if so that's normally the issue with those. What motors does the boat have in it and what are the problems you are having ? Regards Dan

Thank you for your reply! I will go another round, looking for these...

Engines are Mercury HO 496 Magnums from 2003, with less than 100 running hours on them.

I bought the boat in 2014 and had some trouble the first season with the engines stalling after getting on plane. The guy I bought it from thought that it was just some "magnetic pickup valves" (I guess he meant the anti siphon valves that you mentioned) in the fuel tanks that were hung up, and he suggested going out and trying until the boat straightened up... which it actually did!

After running the boat with no issues in 2015 and 2016 the issue came back this summer:
When started, the boat runs great and takes off planing for about a mile or so, then one of the engines starts losing power. If I'm not fast enough to cut back on the throttles the engine stalls and dies. It acts the same right after getting on plane again. Sometimes the other engine acts the same before the first one gets a chance... Last time out I tried to idle back, since one of the engines sounded like it was misfiring when trying to accelerate. When idling back one of the engines eventually died - even during idle speed. The other engine started doing the same, only running for five minutes at a time, then stalling and dying.

I thought this might be something in the fuel, but the engines act the same, regardless of which tank is connected (have one main tank and two smaller auxiliary tanks, feeding one engine each). I have also disconnected the fuel line connections that are threaded into the tanks... It seems like the pick up pipes are built into the tanks and non-removable. It also seems like there are no fuel filters in the bottom of the tanks where the pipes pick up the fuel. The tanks looked clean on the inside.

The​​​​​​ fuel filters were relatively clean. The nets in the inline feeder fuel pumps were relatively clean too...

What should be the next step in trying to locate what's causing the engines to act this way? (Where are the anti siphon valves usually located? They must be hidden somewhere underneath something, along the fuel lines leading to the engine bay, right? I have not seen them anywhere...)

I have a manual system for switching between the tanks, located in the engine bay, in front of the engines, which also lets me shut off the fuel supply to the engines completely.

Any suggestions as to what it might be if it is not the suggested valves?

If you're still reading... Thanks!
Any input is greatly appreciated!