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Jason, Marine Mechanic
Category: Boat
Satisfied Customers: 15883
Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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Yamaha 9.9 ELRX - Can you explain operation of enrichment

Customer Question

Yamaha 9.9 ELRX - Can you explain operation of enrichment solenoid on carburetor. Have 7 ohms resistance, but 12v applied does not lift needle. I followed leads to the alternator assembly (under flywheel). Is this indeed a cranking enrichment device (choke)? RPM related enrichment? How and when is it activated?
Submitted: 1 year ago.
Category: Boat
Expert:  Jason replied 1 year ago.

The enrichment solenoid is called a primestarter. The way that thing works is inside of it there is a heater element that is surrounded by a ball of wax. On a cold engine, when you cold start it. That wax is cold, and what happens is there is a spring inside of the body of the primestarter attached to a needle. When cold, the spring pulls back on the needle, which opens up a fuel passageway, and gives the engine the extra fuel it needs for cold starter. As it runs, the heater element heats up, which melts the wax and expands it, which pushes the needle closed, and leans out the fuel mixture for proper operation. If the primestarter is not working, what ends up happening is just the opposite of a clogged idle circuit. What happens is to much fuel is flowing to the engine at lower rpm, and it ends up flooding out. The easiest way to tell if that primestarter is working is let the engine run at a high idle for about 10 minutes, and then simply touch the body of the primestarter with your hand. It should be very warm to the touch (because of that heater element). If it's cold, it's bad. If its hot, it's good, and the carb itself is clogged. Does that make sense?

Expert:  Jason replied 1 year ago.

I do want to make sure you are happy with my service before you go. If you have a further question on the issue by all means feel free to ask. If not, Just in case you do not understand the way the website works (and some folks do not). You do have to put forth a positive rating in order for it to credit me for helping you. When ratings are not done, the website simply keeps your deposit and they will not credit me. The ratings box is located at the top of the screen. To rate, you must select the star you wish and also confirm it. Please let me know if you run into any problems or errors when trying to do it. If you do have a problem, or if you can not see the ratings box which is at the top of the screen. Please reply back "I rate Jason's service _______" and fill in the blank.

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Thank you,

Expert:  Jason replied 1 year ago.

Hello, just checking in. If there was anything else by all means feel free to ask. If not, please put through a rating on this question page. Ratings have to be done or else the website does not credit me for helping you out.

Thanks again,


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