Have you ever been in the position where you just want to get a job done today? Being of an impatient disposition, I find myself wanting instant results all the time. Especially when it comes to my boat engine.
Having successfully de-winterised my Yanmar YSE 12, I fired it up and looked on as a column of exhaust smoke rose up from somewhere on the engine block. If I’d been as green as when I first bought the boat I would have instantly panicked and been on the phone to a marine mechanic before I could blink.
Yanmar YSE 12 exhaust elbow before removal
This time though, I adopted a more diagnostic approach. The first port of call was the exhaust elbow. I replaced this a few years ago so I know they are prone to disintegration – and I wasn’t wrong. As I watched I saw the smoke clearly emanating from where the elbow joined the engine block. Sigh.
The thing to do would be to replace the exhaust elbow if there is a hole in it (obviously) but I was hoping it would just be a replacement gasket that would be needed.
So I took the old one off, and upon examination it seemed in pretty good shape – except at the top where it screws onto the bronze exhaust bend. Here it was getting a bit too rusty for my liking, but I felt it had a few more miles left in it – so I decided to make a mental note to get a replacement elbow and have it on standby for when it was definitely required.
The triangular gasket is visible
This left the gasket. I felt around the awkwardly positioned hole in the engine block and my heart sank when a crumbling mass of what felt like rusty metal started to come away in my hand. My instant thought was ‘I can replace the exhaust elbow – but not the engine block‘… but fortunately it turned out to be what was left of the gasket. It had become so fused to the engine block that it had started to resemble (and behave like) rusty metal. I carefully peeled it away and reassembled it to satisfy myself that it was what I thought.
Peeling off the gasket
Reassembled exhaust elbow gasket
Here’s where I became impatient and frustrated. I wanted to just put on a new gasket and call it a day – but I didn’t have one and had no chance of getting one for a few days. So resorted (for better or for worse) to using ‘squeeze-on instant gasket'; in this case Loctite Blue Silicone Gasket. On the packaging it said that it could be used for engine gaskets and could withstand up to 200°C… so I thought I’d give it a try.
Loctite Blue Silicone Gasket
I applied a bead around the face of the exhaust elbow join as directed after sanding it down.
Loctite gasket applied to exhaust elbow
Sanded down receiving plate
I also sanded the corresponding face on the engine block and cleaned it as best I could. I then re-attached the exhaust elbow being careful not to over-tighten the bolts – and then called it a day. It takes 24 hours for the seal to cure, so I’ll start up the engine tomorrow and see if it has done the trick.
Re-attached exhaust elbow with instant gasket
Yanmar YSE 12 exhaust elbow attached with Loctite Blue Silicone Gasket
Annoyingly, when I got home I happened to find in my big box of spares both a spare exhaust elbow and a spare (as new) gasket that fit perfectly. That almost never happens. Oh well. At least I have them for when the current one gives up the ghost.
ps. Here is the original exhaust elbow before it was replaced…