Outboard Making Oil - Red Red Oil....

[Girica]

Hey all,

My Honda BF75 is making oil. Obviously it's marked fuel as the oil has gone from gold to pink at 30hrs, and then to dark red by about 100hrs. 95% of my boating is trolling, and it takes me about 5 mins to get to my trolling spot at full throttle.

I'm trying to diagnose the issue before I put the boat back on the water. A couple noteworthy things::::

1. I just changed my low pressure fuel pump after it completely died on me last week. Curious if a slowly deteriorating low pressure fuel pump could cause this oil issue over time?

2. I replaced my thermostats 100 hours ago. The old block thermo was 72C and I changed it to a 60C. Before this change, I never experienced "making oil" or any color change to the oil. I will try to switch this back to a 72C for an assessment.

Any additional thoughts?

Thanks

 

[SpringFever2359]

Sounds like you answered you own question,
Replace the thermostat back to 72

 

[salmonkiller01]

Thermostat not letting engine get to temp. Have had that before on kickers and mains

 

[Capt_Ed]

We put hotter thermostats in our lodge BF90s and it helped a bit but overall the red oil never hurt anything. We put 4000 hours on those engines and still sold them for $1000 . I know guys that are still running them and that's 10 years ago

 

[Samnjoe]

How much oil is it making in 30 hours?

 

[searun]

Most common reason for this problem is an incorrect thermostat - swap it out for the original 72C unit and that should stop the probem.

 

[Coyote Spooner]

As mentioned, I’d change the thermostat, if possible. Yamaha makes a product called Ring Free. Run a small day tank, occasionally, with the appropriate concentration. Run the motor hard, to burn off built up combustion chamber carbon.

 

[Cookie's Cutter]

Also stop running marked fuel. The die gums up carbs and injectors

 

[Girica]

Switched my 60C to the original 72C thermo and remembered why I changed it in the first place - after running for 5 mins the alarm would go off. The 60C thermo doesn't trip the alarm.

I then tested the old 72C thermo on the stove in hot water and it didn't open up until about 82C, and then fully open at 85C. Is that normal or is that a busted thermostat? If it's normal behavior than I'm not sure what next steps to take besides what Coyote Spooner mentioned with the Ring Free. If it's not normal behavior than I'll buy a new 72C thermo and test it.

 

[CIVANO]

Search Assist



A 72°C thermostat is designed to start opening around its rated temperature, which is 72°C (approximately 162°F). It will typically be fully open at a slightly higher temperature, around 77°C to 80°C (approximately 170°F to 176°F).