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  1. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    How much is the plate for the choke on the carb supposed to open? It seems like it should be wide open to me? I will upload a picture when I get home, but it was not vertical after it had been running for 15 minutes or so...
  2. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    I did another dry compression test after running some seafoam through the engine to try and de-carbon cylinder 8 and got: 1 - 170 PSI 2 - 155 PSI 3 - 168 PSI 4 - 167.5 PSI 5 - 150 PSI 6 - 170 PSI 7 - 167.5 PSI 8 - 195 PSI Obviously did not de-carbon it much if at all. I do agree that the numbers...
  3. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    I did not verify the ignition timing, but I have no reason to believe it is off since it was running great, and then all of the sudden not without touching a thing. I will verify tonight anyway. I would not disagree that I have gauge accuracy issues, but I believe the readings in relation to...
  4. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    Really? Even with 190 PSI as my high and 140 PSI as my low? That's a 30% difference and 50 PSI difference. I have an Edelbrock 1409 on there now. I am just going to buy a new carb just to be safe after I finally get the darned thing running. I will do a wet test on all of the cylinders tonight.
  5. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    Wow, it is a lot harder to get a mechanic to work on my boat than I thought! So I have to try to fix it on my own. I was doing some research and I found out that I needed to do the compression test a different way. So this time I took the compression test with all of the spark plugs out, the...
  6. Kola16

    Yam F300 vs. Merc Verado 350 vs. 383 MPI

    I would have sold this boat a long time ago if I could have. The darned thing has sentimental value. My dad bought it new off the lot with his dad. My dad and I did a full resto on it a 5 or so years ago, which included new stringers and a new transom, so it should be sturdy. My dad used to...
  7. Kola16

    Yam F300 vs. Merc Verado 350 vs. 383 MPI

    Ya I understand that. I am a mechanical engineer though so I would hope I would be able to figure it out😂
  8. Kola16

    Yam F300 vs. Merc Verado 350 vs. 383 MPI

    I'm not worried about the work or the cost. I like working on boats as a hobby and boating is what I spend my money on so just want to get the best option out there. I want to ditch the carb though. If an outboard is more reliable or the weight savings is that much more noticeable, I would...
  9. Kola16

    Yam F300 vs. Merc Verado 350 vs. 383 MPI

    Sorry, this is not right. I rented a 22' Hewescraft aluminum boat for a week with a newer F200. WAY lighter boat than mine with an offshore bracket and way less steep of a deadrise. The thing was a dog. Slower than crap. If I stuck that F200 on my boat, it would absolutely suck. My buddy has a...
  10. Kola16

    Yam F300 vs. Merc Verado 350 vs. 383 MPI

    I just realized I put the Verado 400 instead of the 350...Whoops...
  11. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    I took the port side Y exhaust pipe off and inspected the shutters. They were right where they should be in good working condition. The leak was easy to find the cause of, the 3 allen screws had come loose so I tightened those back up when I reinstalled the pipe. I am taking the carb apart...
  12. Kola16

    Yam F300 vs. Merc Verado 350 vs. 383 MPI

    Hmm maybe I am missing something. I would have better fuel economy, better cruising speed, and better top speed with an I/O, but the I/O is the cast iron egg beater? Can you explain this further? I am certainly not interested in putting something less than 300 HP on my boat. I love wakeboarding...
  13. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    Something weird with testing today. When I was measuring the timing today, sometimes the timing light would not light up on the number 1 plug. So I put the timing light on different plug wires for testing and the timing light flashed just fine. Put it back on plug 1 and it would be sporadic when...
  14. Kola16

    Yam F300 vs. Merc Verado 350 vs. 383 MPI

    Considering repowering my boat due to the constant troubles my engine has had. My boat is a 1979 Wellcraft Suncruiser 225, which is the boat in my avatar. The boat is heavy for 22.75 ft. at roughly 5000 lbs. with gear and without main engine or gas. It has a 22° deadrise at the transom without a...
  15. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    I did check the fuel pressure at WOT on the lake. I think it was 6.5 PSI or so, so that checked out. Held pressure well too with the new fuel pump. The old fuel pump did not hold the pressure for very long so good thing I replaced it. I will do the compression test and definitely check the Y...
  16. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    I tested the boat at the lake yesterday. Retarding the timing did seem to help the performance slightly, but definitely did not fix it, as expected. All cylinders had spark too. I am at a loss at this point. I will pull the carb apart again to see if any corrosion is back in there. I will also...
  17. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    Update, so I took apart the carb and blew out on the channels and "stuff" with an air compressor. Got it all clean and particulate free. Put the carb back together to go test it on the lake. Still a no go for the higher RPMs. I could barely plane even with putting the trim tabs down. So I...
  18. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    The corrosion and particulates did not come from the fuel tank they came from the carb. I know this because the same corrosion products were on the non-fuel parts of the carb as well. They stripped the nickel plating and corrosion resistant stuff off the carb after they rebuilt it. Thats why it...
  19. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    Thank you that is exactly what i was looking for! I was calling the jets the wrong thing. The jets are at the bottom of the bowl and that is what the fuel goes through which transfers the fuel out the nozzles. I was calling the nozzles the jets 🥴 I will try to blow out and clear the carb, and...
  20. Kola16

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    I went to get a timing light and a spark gap jumping tester, and the local auto stores did not have a good timing light or a spark gap jumping tester at all. So I took the carb apart and I need some help on understanding how the Edelbrock 1409 carb works. Does the fuel at higher RPMs get...
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