Oil color doesn't look correct

[jackmanjls]

I bought a used boat with a F90TLR, yamaha motor mfg date 11/05.

I changed the oil and the color was like a coffee mixed with some cream, lighter brown. This link:

Using Oil Color as a Field Test

depicts the exact color, see the "Watery" ref.

I let the oil set overnight, looking for some separation and it didn't separate so I conclude that it was not water. I think the only other element is gas? The old oil consistency is thin, not at all like the thicker new oil.

Also, in the bottom of the oil container, for the old oil, I saw some small metal filings. Again a concern.

Keep in mind that prior to buying I took out on the sea trial and it ran great. The engine has 703 hours.

It's currently on the trailor from a water problem that I had earlier. It's a 30gal gas tank and I had it full, the 18' boat flooded the initial time I took it out after the purchase. The water completely covered the gas tank. The gas tank had a corrisoin hole in the gas sending unit ( I live in Fla). This in turn rendered the gas water logged. I had to have it pumped out. I did run the motor during my water prob trying to get back to shore. The motor eventually quit running b/c of water in the fuel line. I now have everything fixed but this oil issue. In the end the water issue was b/c of a bad scupper valve.

My questions are:
#1. Should I do a compression and oil pressure test to determine the state?

#2. How can I verify if the oil sending unit is working?

#3. Is there an audible alarm associated with low oil pressure? If so, how do I test?

#4. Can the command link 6Y8 be converted from oil light to the gauge that's displayed on the 6Y8?

[boats.net]

Run a compression and leak down test on engine, check oil for gas smell,change oil, run for few hours and change oil again to get cleaned up.
It does have a low oil pressure alarm and no Command Link will not show oil pressure on a F90 engine but will show warning if oil pressure is low.

[jackmanjls]

How can I check the audible alarm? I've never heard it and want to know if it is functioning. I disconnected the kill switch and no alarm. On my honda disconnecting the kill sw will sound the alarm.

Also, is there anyway to test if the oil pressure indicator flashes on the CLink?

[boats.net]

Unplug landyard cord and spin engine over, alarm should sound.

[jackmanjls]

In one of the other repsonses it was suggested that I do a comp and leak-down tests.

Keep in mind that I just bought boat so no nothing about the history.

Results from the tests are as follows.

1. the spark plugs looked really good. Engine seems to run good. The idle seems to be little of no vibration, high speed would seem to be normal. No white smoke at the exhaust.

2. comp test with engine hot (cyc 1 to 4): 215, 162, 190, 175

3. leak-down with engine hot (cyc 1 to 4): 75, 30, 50, 52. Line air was set to 80psi.

I could hear leaking from the dipstick hole and through the other 3 cyclinders that not under test. No noticeable leak noise coming from exhaust or intake.

My conclustion is that the rings are weak but since it runs good, no white smoke, no vibration... is there any reason for alarm?

[99yam40]

you can wait on another answer, but Compression and leak down are saying bad things.

Leak down is reported in %.
Did you use a leak down tester?

[jackmanjls]

yes this was a homemade leak down tester.

[99yam40]

Looks like your motor is junk or your testers

[jackmanjls]

99Yam40, this is what I would think but the plugs looked good and no white smoke coming out of the exhaust, idles good, no vibration at hi/lo speed. It seems like there's something wrong.

The leak-down test is fairly straight forward you put 80# of line air through a .040 orifice when piston is at TDC and read the gauge loss, seems pretty simple.

In the end I've made an appt to take to the local yama dealer for some analysis, hopefully professional. The guy I talked with seem to be fairly technical either that or he was blowing smoke.....