foul running OMC evinrude 175 - The Hull Truth

striperboat · 07-08-2007, 07:27 PM

I am the not so proud owner of an OMC version Evinrude 175 '92-'93. I am experiencing the following problems and am looking for help:

Cranking it requires a shot of carb cleaner. It runs very rich, smokey, and will shut off at random times. Under full throttle and acceleration it runs out ok but when the engine is shutoff, an oil slick follows the boat all day. It has a nasty discharge of oily liquid out the exhaust when cranking it on the trailer with the water jacket on.

I have cleaned all fuel lines, replaced the fuel/water separator and cleaned the carbs all to no avail. I run 50:1 premix because the oil injection was horrible. The plugs remain very clean throughout the cranking running/process.

I am wondering if this is sign of lowered compression with the cylinders/rings letting unburned mix go by?

Also asking if there is an internal (under the cowling) fuel/water separator? Bought the engine used and freshly rebuilt from an Evinrude dealer about 3 years ago. Less than 100 hours on it but of course no warranty remaining. It ran good for a season and has been progressively worse each year.

A1 Outboard · 07-09-2007, 08:38 AM

An oily film and excessive smoking is a sign of too much oil, flooding carb(s), incomplete combustion, running too cool, or even a leaking primer "choke".

The motor sounds like it needs basic troubleshooting techniques and an ignition output test. If it is hard starting and you use ether (never recommended for a 2 stroke) then you have "choke" primer problems, plugged passageways, and/or weak ignition.

One thing to check is the intake manifold gaskets and the float bowl and side cover carb gaskets. If they are black colored, get them changed out ASAP. Those black ones swell up with today's gasoline chemicals and alcohol fuels. The proper ones are brown or a reddish orange shade.

striperboat · 07-09-2007, 07:39 PM

Thanks A1!! This will give me some direction. Appreciate your time.

tquan · 07-16-2007, 12:09 AM

I had the same problem with my '91. It was hard to start, smoked like a train, and when you shut the motor off the oil dripped from the prop. Turned out to be the red choke lever. Behind the VRO is a little red lever, make sure it points down.