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  1. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    Not sure; these models are very different than the older ones like mine in that you have a ECM that runs the EFI, not sure if it also controls spark advance or not. This is why I’m not a fan of old EFI boat engines; when trouble starts you don’t have a starting point for diagnosis unless a...
  2. Lou C

    Can I buy a used 302 and use parts from my bad motor to convert it to marine?

    Like Scott said, everything aft of the flywheel is different, if you want to check the only way to know, is to head over to marineengine.com and look at the OMC parts catalog for your year and model, and then compare parts #s and the reality is, most of those parts are NLA, even if you wanted to...
  3. Lou C

    Can I buy a used 302 and use parts from my bad motor to convert it to marine?

    You’d have to get the OMC bellhousing for the GM engine. I agree at that point I’d look for a complete Merc drop in power package.
  4. Lou C

    [SPLASHED] I/O (Sterndrive) Conversion to Outboards

    I bet those guys will be impressed when they find out you built that extension yourself!
  5. Lou C

    Knocking sound from my Alpha One Gen 2

    Just make sure it doesn't fall out. Or, you could run the hose up to the thermostat housing if you can make up an adapter to make it fit. I had a knock like that that drove me nuts for a while after my top end overhaul. It took me a while to figure it out. The cause? I changed the exhaust...
  6. Lou C

    How to run twin 5.0s from portable outboard tanks

    How far are you going and are you just running at idle or slightly above?
  7. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    It's important to see that the cooling passages hold pressure, however, the possible advantage of smoke machine is it will show you where the leaks are. I used it to check a new installation of a 3" Gibson cat back exhaust on my 2007 Jeep Grand Cherokee 5.7. Sounds great (LOUD) and no leaks!
  8. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    also there is an excellent list of informational articles right on this site: https://forums.iboats.com/threads/must-have-technical-information-for-diyers.335378/
  9. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    I'm in agreement with Lpgc here, I would make sure that your results from the air pressure test are consistent, and even though we didn't see evidence of water in your manifolds or exhaust ports, it's still a good idea to test them. So, the only parts I'd order are the gaskets for the manifold...
  10. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    Nope # 4 is the circulating pump hose, #3 is the raw water intake hose, # 2 is the hose to the exhaust manifold.
  11. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    Yep via the raw water intake nipple.
  12. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    The exhaust ports of the cylinder heads, and also remove the oil fill cap, and listen there. after doing the pressure test (12-15 psi) if it fails, I'd probably also try to hook up a smoke machine, like you use for checking out exhaust leaks and evap system leaks, it can make the leak a lot...
  13. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    Not necessary they are out of the loop. We are checking the cooling passages in the block, cylinder heard and intake manifold.
  14. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    You basically have to disconnect the hoses for the exhaust manifolds at the manifolds and use a 3/4" adapter to connect those hoses together with the other ends still connected to the thermostat housing. Then disconnect the raw water inlet hose at the 'stat housing and make up an adapter that...
  15. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    Before you do that, do the air pressure of the cooling system test, very important! A blown head gasket can be tricky, they can leak between cyls, between a cyl and the edge of the block or between a water passage and the cylinder. Mine was the last case, I got water leaking into 2 cyls after...
  16. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    From what we can see, your manifolds and exhaust ports look good. On mine, that pic was when I had the old OMC batwings, I'll have to take a pic of what the reman heads I installed back in '17 look like, next time I take off the exhaust. I had to pull the exhaust off in '21 to get at the...
  17. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    Yes but be VERY CAREFUL with acetone, it's very flammable. I have done it 2x, it's a good test for leaks. Plus you can recapture the acetone and use it to clean stuff (carefully!) when you get em off, take pix of the exhaust ports on your engine and post em up. They should be grey/black not red...
  18. Lou C

    Can I buy a used 302 and use parts from my bad motor to convert it to marine?

    Agreed you need to do a couple days of investigation first. Pull off the manifolds and check them, see if you have rust trails in the bottom of the water passages....that can put water in a cylinder and into the oil Then pressurize the cooling passages with air and see if it holds pressure...
  19. Lou C

    Weird overheating issues

    You have to test the manifolds and elbows as Kenny stated. You can have an external crack from a lack of winterizing that will leak outside but not inside or vise versa. Or, if it's the wet joint exhaust, you can have water seeping in around the joint between the elbow and the manifold. I use an...
  20. Lou C

    Help! Bought a 1993 Four Winns W/ 5.0 OMC Cobra Motor and Drive - Losing power after crusing

    small claims court? well we all get taken at least once I guess mine had a rotted deck I didn't spot, wound up taking a LOT of work to put right but that's 20 years ago and it's still solid now! Live and learn never buy an old boat late model boat 5 years old or newer if you're in freshwater...
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