(just to bring you up to speed on my engine specs)
Mercury 2001 75hp 2 stroke, 3 cylinder.
Been out of the ribbing scene for a few years but have got back into it this week by purchasing a new one
Was very happy with it for the price and shes been looked after, or at least so i thought!
I had been looking for a while for somthing that was supposed to be reliable and thought i found it when i purchased below from Newcastle.
eBay - The UK's Online Marketplace
Checked it all over and it all seemed great, purchased it for £4450 and couldnt wait to take it out today for its maiden voyage around Swansea coast, I had noticed on idle with the muffs on that that every now and then the engine would misfire, but just put it down to it being 2 stroke as the idle can be more erratic than a 4 stroke. I had also compression tested the engine on purchase and it had about 138psi across all 3 cyclinders all within 1psi of each other so thought that was spot on.
So we had been out for about 2 hours and on the way back about 1km from the slip the engine started to develop a intermittent misfire, which then turned into a serious one. I heard a loud pop sound from inside the engine cowl and then there was a distinct patter sound followed by very rough running (sounded like an exhaust inside the casing). We took the engine cowl off and noticed that a pipe had literally exploded and the air pressure was being blown from the pulse pipe on the fuel pump. When it was misfiring it was backfiring through this small pipe. I have included a video and photos below.
We managed to limp back with the engine running terrible, we were glad we were not any further out.
Can anyone explain to me what has happened! I am well miffed on my first day back out!!
You can see where the backfiring gasses have actually melted the sound proofing inside my cowling!!
This is the fuel pump, fuel in the bottom with the oil and it goes out the top, the other pipe which is the one which were all this pressure is coming from is the "pulse pipe" acording to the manual. When the engine is running there is a significant amount of air pressure coming out of this hole on the block. Is this normal, also when it was back firing, it must have been igniting the fuel mixture that was in this pipe! (you can see it melted the pipe inside and split it open)
Here is a video also
VIDEO0016 - YouTube
Can anyone shed any light on whats happened, i need to replace the pulse pipe as its shattered the fittings so i cant repair it, but i dont think this is the sole problem. Your thoughts would be appreciated