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Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3714
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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Yamaha 175tlrv outboard: engine idles well but stalls or

Customer Question

yamaha 175tlrv outboard:
engine idles well but stalls or runs raggedly with backfiring when the throttle is opened. The fuel is fresh and coming from a clean portable fuel tank . the filter /water separator has been replaced. fuel pump pressure is 4-5 psi from each pump. The carburator progression jets are clear (one of 18 was clogged when checked). New spark plugs were installed. All the old plugs looked the same (wet but not unusually black) when removed.
Submitted: 1 year ago.
Category: Boat
Expert:  Charles replied 1 year ago.

Hello, my name is***** will assist you today.

Has the boat been siting for some time unused?

How old was the fuel?

Has any other work been done to the boat?

Customer: replied 1 year ago.
Hello Charles:
1. The boat has been sitting for months. It is run a couple of times a month to keep the batteries charged.
2. The gas is about 3 weeks old and ethenol free marina fuel. I'm running from a new portable tank and new feed lines
3. 2013: Engine overheating problem. Repairmen treated the engine ( flushed with acid) and over heating stopped.
Engine quit due to an ethenol problem. Carbs were cleaned of considerable sludge,lines flushed, filter replaced.
2014: Engine quit due to water in system (filter/water separater failure??). Carbs etc. cleaned and filter replaced. Main fuel tank removed and portable tank used since.
2015: Declining boat usage due to health problems. The current engine problem started in the spring of 2015.
Expert:  Charles replied 1 year ago.

How long did it sit before the spring this year?

I have to log off and get to a football game.

I will look for a reply when i get back home.

Customer: replied 1 year ago.
The boat sat for a couple of months with only the engine run without leaving the dock to charge the batteries.
Expert:  Charles replied 1 year ago.

Hello again,

The first thing that you need to do is to check the fuel for any water in it. If you bought it at a marina, there is a good change that you have water in it.

If there is no water in it, you are going to need to remove the carbs and totally take then apart and clean them. When an engine sits and the fuel evaporates out of the carbs, it leaves behind a varnish that will clog he small jets inside the bowl of the carbs. After this is done, your motor will be running again.

Customer: replied 1 year ago.
I will do as you suggest and let you know how I make out. Thank you.
Expert:  Charles replied 1 year ago.

Your very welcome. Please let me know.

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