yanmar 4lha-ste engine temp.

[David Moore]

Starboard is burning more fuel, higher temp, slightly higher oil pressure and minor darker exhaust vs the portside. (only happens when 2500+ rpms / cruising out)

Any ideas? heat exchanger? too much fuel/burning rich?

Thanks!

Engines:
twin turbo diesel yanmar 4lha-ste

Topic

[Bill Fuller]

I’m sure Tony will answer, but here are a few items.
Sending units and gauges must match each other. Motors don’t care what they are.
That is very fast for that boat and RPM. Are you running really light?
Alternator belts are a real problem on these motors. It is very difficult to keep them adjusted. Continually getting loose. I have found that these belts are by far the best to use. They stay adjusted for hundreds of hours. Only cost about $10 from Amazon.
by D&D PowerDrive
D&D PowerDrive RECMF6460 Mitsubishi Motors Replacement Belt, 17, 1 -Band, 47.27″ Length, Rubber.
They are a bit tight and difficult to get on the first time, but well worth the effort.
At cruise motors should run about 178 degrees.
What color is your coolant? Coolant is critical on these motors.
If you are interested I can suggest a number of things for you to address. Sounds like you are already addressing a lot of them.
where are you located?
My motors are now just a bit shy of 6,900 hours, and over the last 20 years with them I have come to know them quite well.
Great motors.
Bill

[David Moore]

Hi Tony,

Thanks for the reply. I think we found the issue. I believe it had to do with the belt being a bit loose and then slipping at higher rpms.. unfortunately the old mechanic stripped the belt tensioner on the alternator so now I have to get the female thread side tapped and upped a notch. Hopefully that goes smoothly.

The gauges seems to be acting up as well(engine temp/oil pressure). They are the original 1979 Phoenix gauges. Do I need to contact yanmar and get specific ones for the engines or does it not matter long as its the same metric system.

Thanks again for your help.

As to your questions:
1) Last time the aftercooler was removed from the engine, put on the bench and cleaned per my protocol? I purchased the boat a few months ago so I cannot be certain. I know the fluids were changed 4 months ago. This is on my list to do regardless if issue is fixed or not to have a good baseline.
2) WOT RPM loaded as you use the boat? Cruise RPM? I typically cruise 2500 RPM and gets me about 20-22 knots, max test was 3300 and 33 knots.
3) Total hours since new? turbo diesels, 230hp each, installed year of 2000- 3000 hours.
4) Post real good pictures of the turbo and the exhaust mixer/riser that is attached to it–A few angles. I will snap some later this week.

[Tony Athens]

Yanmar 4LHA-STE dark smoke issues

Answer these questions:

1) Last time the aftercooler was removed from the engine , put on the bench and cleaned per my protocol?

2) WOT RPM loaded as you use the boat? Cruise RPM?

3) Total hours since new?

4) Post real good pictures of the turbo and the exhaust mixer/riser that is attached to it–A few angles.

Start with that.

[Author]

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