2005 50hp Mercury Low Water Pressure and High Fuel Use

[scott2h2]

I have a 2005 50 hp Merc on a 21' Sun Tracker Fishing Barge. I went out today and noticed that at wot, 5200, the water pressure gauge was reading 10psi. That seems low. Also, it is using more fuel than last season and seems to have more vibration as well. It starts on the first turn of the key with no problem and does not bog down. The impeller was replaced last year. What should I be looking at? I was thinking of pulling the plugs this weekend to see if they tell me anything. The motor has only been in fresh water.

[1nebel0]

The first thing you need to do is check the compression...the second thing to check with spark testor is that you have spark for all cylinders...once you determine that you can move on to other things such as lync and sync, timing etc...the water pressure for Mercury is a little low but not bad...impeller should be changed anual given the size of these pumps. Vibration can also be the prop..hit something last year? Good Luck

[scott2h2]

I forgot to mention that it is a 2-stroke if that makes any difference on where to look.

[carholme]

Scott;

Before you start tearing the engine apart, what engine do you have? What is the s/n? There are 2/4 stroke engines.
Do you have a manual and have you read the specifications for your engine?

If it is a 2 stroke, those numbers are in the correct range. If it is a 4 stroke, a bit low on both counts.

Send us the s/n and I'll get you the correct manual for it so you can see for yourself.

But don't just start tearing things apart and making conclusions without knowing what you have.

Gerry

[scott2h2]

The s/n is 1B153828. Also, the prop is undamaged. I do not know when the last tune-up was done so I plan to change the plugs this weekend instead of just cleaning them. I would prefer to not tear anything down on the motor.

[carholme]

Scott;

That s/n comes up as a model:

1050412DD MERCURY 2005 50

Parts listing:

http://www.crowleymarine.com/mercury-outboard/11493.cfm

Service Manual P/N: 90-852572R02

http://1manual.com/Mercury%20manuals...72r1/cover.pdf

You must have Adobe Acrobat reader installed to use this manual. If you scroll down to the lower part of the opening page, you will see the various engine components in red. Click on the one you want and when the first page opens, click on the "Save As" icon at the top LH corner of the page and you can save it to your computer.

Gerry

[scott2h2]

Thank you for the info. I greatly appreciate it.

[carholme]

No problem Scott, let us know if you find anything.

Gerry