Volvo Penta Running Rich - Page 4 - SailNet Community
Old 11-20-2007
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Quote:
Originally Posted by erps View Post
Not trying to beat a dead horse but just breaking it down a bit so I can understand it....

Take two mason jars, each the same size, and put the lids on them. Apply a vacuum of 20" on one of the jars. Which one has more air in it? (20" is the vacuum a gas motor pulls at idle) I don't think the restricted air intake on a gasoline motor can be discounted.
Gas engines use throttle plates to restrict the RPMS.

A Diesel uses the specific injector calibration (mm3) at a regulated fuel pump pressure which is limited by the governor to restrict the RPM's and that's why the Diesel intakes are big so there wont be a vacuum.

Ken, East Prov., R.I. Bootlegger, PY26 Paceship

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Old 11-20-2007
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Quote:
Originally Posted by Rockter View Post

So, if the temperatures are 10 degC and 50 degC respectively, convert both to the absolute temperature scale (just add 273 to both) and write as...

rho1/rho2 = (50+273)/(10+273) = 323/283 = 1.1413

...or about 14 percent more dense.

The motor would rather breathe the denser air.
On a typical boat gas engine w/ a computer, the computer would compensate via the O2 sensor and meter the injectors.

On a typical boat diesel w/ just a mechanical fuel pump, it would just run leaner w/ denser air. same fuel/more air = leaner.

Next,
Put the same diesel boat in a lake (if it exists) in Denver Co. and the lack of air density @ 1mi. above sea level and POOF! it will run richer. This is why older cars in higher elevations had to get the carbs. re-jetted smaller.

A gas engine boat w/ computer would run the same because the computer would compensate.

I'm still betting the OP just needs to really clean the injectors....

Ken, East Prov., R.I. Bootlegger, PY26 Paceship

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Old 11-20-2007
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Take the engine covers off and tell us what happens. Does the black smoke reduce?
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