PBO reader Gunter Bock wants to know what’s causing his smoking boat engine. Our expert has this advice…


Gunter Bock from Norway writes: “I read in PBO’s November 2021 issue about exhaust elbow problems. You recommended replacing the reader’s damaged iron elbow with a new one in stainless steel.

“I’m wondering whether there are any galvanic problems in combining stainless steel with an iron motor block? I’m running a Volvo Penta D1-30F.

PBO engine expert Stu Davies replies: “There are quite a few suppliers of aftermarket stainless steel exhaust elbows out there. Stainless to cast iron should not be an issue.

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“I actually made a stainless elbow for my Volvo Penta MD22 which has an aluminium heat exchanger. The gasket off the original Volvo Penta elbow is stainless steel.

“I reused it. If anyone was going to have a galvanic issue it would have been me – but I haven’t.

“I’ve also spoken to the managing director of parts4engines.com and he also makes the point that Volvo Penta use stainless steel gaskets.

“He has stainless steel elbows made in 316 stainless and his gaskets are actually fibre and ordinary steel, so if you did have any concerns at all, the use of one of these would give some reassurance.

“Another interesting point is that your engine is based on a Perkins 400 series motor.”

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This feature appeared in the November 2022 edition of Practical Boat Owner. For more articles like this, including DIY, money-saving advice, great boat projects, expert tips and ways to improve your boat’s performance, take out a magazine subscription to Britain’s best-selling boating magazine.

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