If you have vortec heads you need the longer plug
If you have the 1986-1995 swirl port heads, you need the LTS (short)
Since you have 12 intake bolts, you have the swirl port heads
Looking at the plug, you are running lean and hot.
Backflush from the raw water pump to the propane. If the pump has muck in it, you need to flush the line to the thermostat.
If the thermostat housing has muck in it, you get to flush the exhaust manifolds and the long block
Teleflex sold off the gauge business and the cable business many years ago
Look at seastar which is the old teleflex cable company
Generally you replace the helm and cable as a unit
If it's vortec, it's not adjustable unless there is aftermarket valve train.
If it's adjustable valve train, then between 3/4 and 1 turn after zero lash
When the torsion axle on my RV failed last year, it took out the frame. Yes, LCI sent a new axle, yes they offered a new frame, however it would have been months waiting.
I have a love/hate relationship with torsion axles
the only difference between your boat motor and a truck motor is the head gasket, the core plugs, starter, the cam and the raw water pump. the ignition and induction were added by volvo along with the exhaust.
your "marine" flywheel is nothing more than a GM manual transmission flywheel.
the...
I have a half dozen spark plugs sockets I ground down over the years to fit in various areas.
I have busted the insulators a few times to get a short socket on the base for removal
