Volvo Penta D1-30 smelling like burned plastic

B37Skipper · #1 (**permalink**) 11-06-2011

Experts,
I just noticed that the Penta D1-30 I've got in my Bavaria 37 smells like burned plastic at around 1500 rpm or more. My normal cruise rpm is just under 2000 and when I'm in a hurry I can run it for short distances up to 2300 rpm. Now it refuses to do more than 2000 rpm and the exhaust seems blacker than normal.
It starts without issues, everything looks like it is tight and clean. Sea water filter is clean. Fuel filter tight and recently changed with the oil as part of the annual service.
What could be wrong and what should I check?

dabnis · #2 (**permalink**) 11-06-2011

Burnt plastic? Is it running hotter than normal? 2,000 RPM max? Fouled prop?, plugged mixing elbow at exhaust manifold?, very dirty bottom? Restricted air intake from bugs or whatever? Did this just happen or did it come about gradually? Besides the work you did, has there been any other work done lately? Let us know what you find, always interesting to learn from other's experiences.

Dabnis

B37Skipper · #3 (**permalink**) 11-07-2011

Dabnis,
Yep distinctive burning plastic smell only at 1500 and above RPM. No smell inside the boat or from the engine compartment. It is not running hotter than normal, as far as I can tell - there is no alarm. It refuses to rev more than 2000 RPM but is running like always until then. The prop and bottom is definitely not fouled, it was out of the water about 2 months ago for a proper clean. This just happened now this weekend. My co-owner had a chat to a diesel mechanic today who thinks the exhaust may be blocked so will let you know what the outcome is. Any other input from you experts is valuable and hopefully reduces the bill from the mechanic ...

TQA · #4 (**permalink**) 11-07-2011

Quote:

Originally Posted by B37Skipper

Dabnis,
Yep distinctive burning plastic smell only at 1500 and above RPM. No smell inside the boat or from the engine compartment. It is not running hotter than normal, as far as I can tell - there is no alarm. It refuses to rev more than 2000 RPM but is running like always until then. The prop and bottom is definitely not fouled, it was out of the water about 2 months ago for a proper clean. This just happened now this weekend. My co-owner had a chat to a diesel mechanic today who thinks the exhaust may be blocked so will let you know what the outcome is. Any other input from you experts is valuable and hopefully reduces the bill from the mechanic ...

Check the prop before you do anything else, 2 months in a high fouling area and you might have a flowerpot or barnacle farm for a prop.

dabnis · #5 (**permalink**) 11-07-2011

If it just happened there may be some line or other debris in the prop. Hot plastic smell not in the engine compartment? Binding cutlass bearing or again, plastic bag or poly prop rope bound around shaft? Not sure if blocked exhaust would come on so quickly unless a crimp in the hose just happened?

Dabnis

Capt Len · #6 (**permalink**) 11-07-2011

Assume that the stuffing gland is OK and that the engine hasn't gone off alignment and that the v belts haven't started to unravel . the air cleaner is good and no one stuffed a potato up your pipe the problem could be a plastic bag around the shaft.

B37Skipper · #7 (**permalink**) 11-14-2011

Problem solved: Blocked exhaust elbow.

For future searches on this topic;
According to the diesel mech they do block up every 5-7 years. The boat is located in Sydney, Australia used all year around by the three families sharing it. The blockage happened at around 450 hrs of usage on a 2007 Bavaria 37. This boat has sail drive so in this case there is no traditional prop shaft that could cause that type of issue.

Thanks for all the suggestions regarding this!