I finally got the boat in the water this past weekend, but the engines are hard to start. I installed two new battery's and two new starters but the starters are weak and don't seem to be getting all the "juice". On both battery's the negative post gets so hot after trying to start the engines that you can't touch them. I'm thinking my negative grounding point is not sufficient and is creating alot of resistance.

When I pulled the engines/tranny's last fall and stripped the bilge, I failed to not where the factory grounding point was so I connected the negative battery cable to the engine block using one of the bellhousing bolts. Does anyone know where the factory grounding point is for a TRS/Velvet Drive setup? There is no 3/8" stud for the negative cable on the starter itself. I was thinking one of the starter mounting bolts might be a better grounding point.

Any spot near the rear of the engine block should be sufficient. I use a bellhousing bolt.

I used double cables to two separate bellhousing bolts, making sure that the area on the bellhousing where the cable end touches the block was paint and rust free and then once torqued down, painted the area to prevent corrosion. Also used double cables on the positive to the starter, as I had 10.5:1 high compression 406 CI SBC. Before the retrofit, the high torque starter would "labor" to turn the motor over.

If you have a twin engine boat... you also need to run a ground cable between both engines.... That way if you use "both" batteries on the switch.. you will get a current flow from both batteries... if the engines aren't grounded together... you will only get a current flow from the battery that is connected by the ground cable... regardless of what the switch says.

Thanks guys, I didn't know about needing a cable between the two engines. I'll try cleaning the paint off the grounding point and adding a jumper cable between the two engines.

The problem is the connection that is getting hot! Resistance creates heat. You should be able to put your hand anywhere on the cable.

Reed is right, you must have a large ground between both engines. The main reason for this is safety. If you loose a ground during cranking you don't want 600 amps trying to use a 10g wire that is routed through your dash back to your battery!

Steve H

I run a ground from each battery to each engine.

What size is the cable? Should be a 2/0 cable not a #2. Yeap Reed is right about tying the two engine together. I also tie the negative side of each battery together with another cable. I would be inclined to think that you just have a bad connection on the cable, either dirty (paint) or rust on the terminal end. Also check the tightness of the ring terminal on the end of the cable, could be loose here also. Oh yeah, I use a mounting bolt for the oil filter on the head for a grounding point.
Robert

A friend of mine had the same problem with his 406 sbc. It was corrosion in the crimped cable end. He replaced the cables and BINGO!

Run largest guage possible to bare metal on the blocks. Use brass terminals if you can find them.

Roby