No expert here but I would first try to do the simple things. Also I've been told those pumps rarely fail.
My experience is with a D4. We live on the boat half time and ruan it hard all last winter and this.
Is the voltage open circuit or with the pump running? If open circuit then you have an electrical
problem for sure. Even if with the pump running it may be an electrical
issue. My D4 draws quite a bit of current
on start up, you may have a high resistance connection, or high internal resistance in your batteries.
I would try charing the batteries and start it with the charger
running, then see if you get this same drop. If you do, then I would suspect the electrical circuit.
There is a glow plug
in the unit, and a special tool to remove it. It just a deep well socket with a slot cut to accept the wires. Underneath the glow plug
is a wire basket that will foul after some use. It needs to be changed. I did this for the first time Saturday but saw it done one other time. PITA. I used a small diameter corkscrew to remove the old screen
, but I had to take the damn thing apart to get at it sufficiently. Sometimes you can get it without disassembly.
Go to EsparofMichigan to order the spare parts
. The mesh will come with a plastic insertion tool. Order a gasket
at the same time, its recommended to be changed and mine was toast. With the new mesh in hand you can visualize trying to dig it out of a tube about an inch deep and find the appropriate tool. Maybe even a drill of the right diameter would work.
That should cost under $20 for tool, mesh, and gasket