alright, spent saturday troubleshooting. easy things first:
1. prop was not dirty enough to cause problems. but i scrubbed it nonetheless, since i was in the water
2. air filter is not pristine, but i don't think it's really an issue (i will change it since it's cheap
enough to do even if i don't need to).
3. fittings: this is where the problem may come from. i have those swivel fittings, with hose barb (no clamps) on one side and female nut + compression
thingie on the other side. these look like parker/racor push-lok style fittings (straight, with a yellow plastic ring at the end of the hose), but i'm not entirely sure. i couldn't figure out if the thread is SAE (straight) or NPT (tapered), so i may have put the elbow
into these fittings the wrong way around (elbow has one side jic/straight, the other side NPT). so the threads are now partially stripped. i managed to put them back together and it holds (and i got the engine
to 2400 rps umder load, getting boat to hull
spead, but couldn't rev higher under load - i wonder why), no leaks
, with megaloc as goop.
4. i put in a gauge via a regular t+insert (since i couldn't find a street t), and the gauge is working properly: first when i started the engine
i forgot to open the fuel supply line, and although the lift
pump clicked and the engine actually ran fine (out of gear
, idling only) the gauge got to about 15 which is in the red zone - when i opened the valve it dropped to almost zero which is how it's running now, so the lines and filter are probably fine.
given this behavior, i would guess there should be some air leak in the system at the fittings (otherwise how else would the engine manage to run for half a minute with the fuel shut-off valve closed). i would also like to replace the fittings.
the problems with the fittings are these though: the hose size is 5/16, and i can't seem to find fittings for it easily anywhere (on the web or locally; autozon/napa etc automotive stores are not helpful here). and the other issue - how do i remove the existing fittings? i could of course go the barbs+clamps route
, but i guess whoever installed this originally decided not to, so there must have been a reason for that.
thanks again, any suggestions greatly appreciated!