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  1. M

    70hp orifice change

    Better late than never! I finally received my power pack. The CDI trouble shooting guide was very helpful. I was able to test the old power pack with their direction. sensor 1 ohmed out at 87.8 ohms, sensor 2 at 119.5 and sensor 3 at 98.8. I checked the timer base as well and it tested...
  2. M

    70hp orifice change

    Racer, I am a bit impatient! I saw an ohm test from CDI for the power pack but it doesn't really go into detail. Am I supposed to disconnect the battery or spark plugs or anything else for that matter before I do this test? My new power pack will be here Sunday and in the meantime why not do...
  3. M

    70hp orifice change

    Last night's test run was partly a great success. This motor does not require the extra vacuum hole in the back of the fuel pump. I was able to cruise the lake, WOT. My problem now is a misfire....... It mostly happens at mid range. With the timing light on I was able to see the...
  4. M

    70hp orifice change

    I found something upon my fuel pump inspection. The new fuel pump has an open hole between the 2 mounting screws, the mounting gasket has the same. The original does not. I purchased a rebuilt kit that was for this motor but...it was sized for the new pump that I was inspecting. Dungar...
  5. M

    70hp orifice change

    Thank you Racerone, I'll repost the results.
  6. M

    70hp orifice change

    Sorry I need to add... At WOT it wont die but it does surge. Rapid surge too a bit more than a second apart. Gets up to 5100 rpm 29 mph when it surges. It does have a bit of a shudder mid range as well.
  7. M

    70hp orifice change

    Racerone, The motor starts up very easily. It will die after a bit of running in gear at low idle too. When I look at the fuel lines to the carbs there isn't any gas in them, they are clear. So I pump the bulb until I see the fuel in the lines and the bulb gets hard and it will start up again.
  8. M

    70hp orifice change

    Will do. Will compression effect the fuel delivery?
  9. M

    70hp orifice change

    All compression numbers were about 100 the last time I checked. I've tested with 3 compression testers and they are anywhere from 115 to 100 so I go with the lowest reading! Your right it did have a bad exhaust leak and I pulled the powerhead and resurfaced all the plates. I did the same to...
  10. M

    70hp orifice change

    70473M 1974 EVINRUDE 70HP
  11. M

    70hp orifice change

    Good to know Racerone. So why am I not getting the fuel the motor needs? Weak pump? I had the system under pressure all night and the bulb stayed hard and the lines to the carbs are full of fuel and I don't see any leaks. I'll have those core plugs #4 and #5 in a day or so. Could those...
  12. M

    70hp orifice change

    Well I was able to get all the fuel leaks fixed, SO I HOUGHT! I had a float valve that had a bit of something down in the seat. Cleaned it out (top carb) cleaned everything with carb clean and compressed air. Put it back together and it appeared to hold pressure. I replaced the carb fuel...
  13. M

    70hp orifice change

    Thanks for all the good advise Oldsaltydog, I did not remove core plugs #4 and #5. I will this week. I did replace 1 one the high speed jets because the screw driver end was pretty stripped out. I'm ordering the other 2 this week. All #39 nozzle gaskets have been replaced. I did clean the...
  14. M

    70hp orifice change

    Adding to my last post.... I fixed all the fuel leaks except one. I have 3 carbs when I pump the bulb fuel leaks from the top carb out the throat. I pinched off the fuel line to that carb and my fellow system holds pressure. Something tells me the top carb has a leak. Probably from a needle...
  15. M

    70hp orifice change

    Ok back from the lake! New fuel lines and inline fuel filter along with a quick carb cleaning made an improvement on my sudden drop in RPMs from WOT. But....still had the issue. Just not quite as bad. I did the timing light check on each plug wire to rule out a power pack problem my results...
  16. M

    70hp orifice change

    I haven't tried that but after my fuel delivery overhaul. I'll give it a go. New hoses plus a filter and a carb cleaning, new float seat and needle. Adjust float drop and level. And the typical cleaning. Granted this will be the 3rd cleaning in 3 trips less that 2 hours a piece.
  17. M

    70hp orifice change

    The alarm works and yes I replaced the water pump this last June. While on the muffs I'm able to keep a hand on the exhaust plate, Its hot just not hot enough to burn you. I know that's not very technical but I don't have an infrared thermometer. Again both poppets, springs and thermostat...
  18. M

    70hp orifice change

    Thank you Racerone. I'll get these carbs back together and test it by the end of this weekend and repost of course.
  19. M

    70hp orifice change

    Racerone, Sorry let me clarify the fast idle pump. I do it after the motor has started. Kind of like reving the engine in a hot rod! Just knocking the cobwebs out!!! Do you know of a bench test that will diagnose a high rpm short in the power pack? Or am I hanging off the transom with a...
  20. M

    70hp orifice change

    Is there a bench test that would be accurate knowing my issue is at high rpm? It starts just fine with the auto choke and just a few pumps of the cold motor idle lever at the controller. I did forget to mention the link and sync is perfect, by the book.
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