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Marinize LS1

05-05-2021, 03:37 AM
Hi, I have a Chevy LS1 motor out of a Commodore Automatic 4WD and want to put it in my ski boat. It has a cable operated throttle body. I have seen a marinized version of the LS1 in a ski boat and it uses a MAF sensor and no oxygen sensors.

Please is someone able to tell me how to set up my motor to work the same. At a pinch I may be able to run the pre catalytic oxygen sensors, but I have read that there may be a problem with steam.

Blue Bowtie
05-05-2021, 06:13 AM
Most I/O engines I've been around are Gen I SBCs, and all have had cooled exhausts (logs). It would seem that you would need the same if you are running submerged exhausts.

Then there is the mounting, driveline, and water pumps.

Is this a stern drive, jet, or V-drive application?

05-06-2021, 03:23 AM
Thanks Blue Bowtie. The boat is a center mount with a clutch and propeller shaft set up at 12.5 degrees. So pretty simple and I plan to run an offset velvet drive with the LS1. It will also need fresh water cooling.

Blue Bowtie
05-06-2021, 07:06 AM
Another option is a carb and intake, ignition box, and open exhaust (over the top) if simplicity is the goal.

There seem to be aftermarket accessory seawater pumps available. There are even aftermarket exhaust logs with cooling loops and OČ sensor mountings, and it's limited only by your budget.

05-07-2021, 12:16 AM
Thanks Blue Bowtie,

Interestingly the marinized LS1 that I have seen has the ports for the precatalytic oxygen sensors and doesn't use them. It would not be that expensive to set up that way and the motor may run better. I am aware that there are dummy post catalytic sensors that give a false OK reading to the computer.

Basically I am on a budget and am trained in the mechanical field so that I do what ever I can myself.

05-15-2021, 04:56 AM
Hi everyone,

I have been researching how to marinize my LS1 and have found out that LS1s can run well in open loop. Correct me if I have got this wrong, as I understand it if the computer does not get an input from the oxygen sensors it will run in open loop.

From what I believe this just means that the motor will run a little rich. I suppose that would still be better than a conventional carby setup.

Thanks in advance for your suggestions.

Blue Bowtie
05-15-2021, 08:48 AM
Depending on the PCM programming, it is likely that the lack of an OČ signal over a period of time will set a DTC, and that could result in loss of beneficial ignition timing advance. A reflash of the PCM could solve a lot of that, of course.

05-17-2021, 05:23 AM
Thanks Blue Bowtie. Yeah I need to learn how to flash the PCM to remove the anti-theft and some other redundant elements.

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