Yamaha 60 2 stroke rattle
My Yamaha 60 autolube has always had a certain rattle to it.
It's been fine all summer though with many trips, pushes the boat at 40mph no problem, good compression etc, just sounds like a box of spanners. It's not bothered me too much as it was just a cheap stop gap engine (built 1989) to get me out on the water while I wait for the right 4 stroke 40 to come up for sale. Now, having gone all summer without it missing a beat and realising its not as bad on fuel as I thought it would be, I'm thinking of keeping this motor and ironing out some of its little annoyances.
I'm used to 4 stroke engines and to be honest thought that the noise it was making was normal 2 stroke rattle. Imagine my surprise when, last time I put it on the water, it was ticking over on fast idle to warm up and suddenly stopped rattling for a few seconds (it was still running) and sounded all lovely and smooth and nice!
The fact that it is now an intermittent rattle tells me something is wrong and hence may be fixable. Any ideas what this could be?
The rattle is a plasticky tappety, fluttering noise, quite loud compared to the rest of the engine at tickover. it sounds like an old 1.1 fiesta with worn out tappets.
Now, when I first got this motor, I went mad and disconnected the autolube system and premixed it as the engine was of unknown provenance and I mistrusted the autolube. Following the advice of a local (non Yamaha) outboard specialist I did not set up the tank oil to circulate the pump as I was told running it dry would do it no harm and if I wished to reinstate the autolube I'd just need to reconnect the pipes and prime it and it would all be good to go again. When I got sick of poisoning myself and passengers with 2 stroke fumes on 50:1 premix I refitted and primed the autolube system, which seems to be pumping oil in OK, though I am still doing a 100:1 premix in the tank to be on the safe side.
Could this horrendous rattle be a dodgy automix pump? Could they all sound like this? I had an Optimax 225 that sounded similarly horrid at tickover and then found out they all have horrible rattly pumps at tickover.