Merc 7.5hp question

[cheetahgod]

I have a 1980 7.5hp merc serial number in the 57000s. My inlet needle doesn’t have a spring. I may have lost it but I’m not sure if it’s supposed to have one. Thanks

[billw]

They did have springs, which are a pain in the butt. If your float sits parallel to the carb body when held upside down, I would go ahead and try running it and see what happens.

I had a 50 Merc, with a pair of that type of carb on it. I was constantly having flooding issues when priming, even with new parts, new floats, etc. I finally found some used, solid needles out of some old Yamaha that fit well, and tried them. The engine never worked better. These engines are known to run well anyway; but this one was the best I have ever heard, after that mod. Disclaimer: I never tried it on a tilted power head 7.5 or 9.8, so your results may vary.

Long live American manufacturing!

[cheetahgod]

Do you know what the parts number is?

[mercuryspecialist]

I haven’t experienced the need to utilize a inlet needle without a spring, but I do remember at least hearing of it (I believe that we have always utilized a needle with a spring ourselves). I think the needle without a spring is 1395-803861 from Mercury, but you can purchase (3) of the recommended needle (with the spring) for each one without (we have both). The float setting differs depending on which float is in use (coated foam – early, or hollow plastic – late/current)

Regards,
Joe

[cheetahgod]

I checked the part diagram and it says the correct needle is part 1399-6141 which is different to the one you suggested.

[mercuryspecialist]

I would have thought that a 1980 model would have a Walbro carburetor, but if you rather have a Tillotson, then of course the number you mention is correct, and it doesn’t have a spring. My comments were based on having a Walbro. The information about the float setting, I believe, still applies with a Tillotson also.

Regards,
Joe

[cheetahgod]

Thanks for the help.

[cheetahgod]

thanks for help. Got the engine running. Is gas supposed to leak out of carb if when you prime the engine?

[billw]

No. That’s usually what happens when the inlet needle HAS a spring. However, if you are running in a test tank, try simulating a more usual boat transom angle. Since the power head is already angled, sometimes the added square angle of a test tank is too much. If that doesn’t help, I would go back and think about a new needle and seat and/or float.

Long live American manufacturing!

[cheetahgod]

I have already replaced the
Needle, float and the various Gaskets.

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