Some thoughts on Volvo-Autoprop issues

rbenven44 <no_reply@...>


A couple of years ago, I posted my experiences with the Volvo RPM
issue, but I'll repeat them now to address the recent questions. I
have SM #195, 1997 model, with Volvo Penta TMD22 and Autoprop.

In July 2002, while in the Azores, I found the engine not giving
me full power. I had the injectors cleaned, but still could not get
over 2100 RPM. Cleaning the prop did not help (I have a Brownie's
Third Lung, and spent a lot of time underwater cleaning the prop to a
fine polish!)

In September, in Lanzarote, I removed the turbocharger (very easy)
and took it to a diesel car mechanic in Arecife. He cleaned the
substantial carbon deposits from the "hot" side (the turbine that is
powered by exhaust gases). Cost was 60 Euros. I immediately was
able to get 2800 RPM underway, and speed increased from 7 kts. to 8.6

My theory is that substantial motoring at 2000 RPM or less (to get
good fuel economy) leads to this problem. The turbo is designed to
boost power at high RPMs, and the engine needs to be run at full
power from time to time to use the turbo and "burn off" the carbon in
the turbine. Amel recommended this to me when I bought the boat, but
the thought of running the engine flat out for 5 minutes at a time
scared me. I now do it at least once a month, and still get full
power, even with a dirty prop.

For those of you with Volvos not getting full power or full RPMs,
clean your props, but also clean your turbos. It's very easy to do,
and I'm sure you'll see results.

Roy on Excalibur SM #195

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