Sorry for the length...
I purchased and moved onto my sailboat just over a year ago, and have slowly been going through each and every system, learning
it top to bottom. Finally I have tackled my engine
- and just in time, as she had stopped running.
The previous owner apparently had a breakdown somewhere; he blew out his fresh water
impeller and overheated, burned a hole in his water
trap, and had to make modifications to get home. He rerouted the raw water
intake through the main engine
- not that bad a thing, apparently, the instructions on how to do this are in the service
I left the engine this way for a year, not knowing any better. She ran pretty well for the year, though near the end of the summer she started giving off a fair amount of white smoke after running for more than a few minutes at a time. I stuck around an anchorage for a few months without moving, but then when I tried to move, she made it a few hundred meters and died and then wouldn't start again.
In an effort to get on top of the engine, I took a marine diesel
theory class, and paid attention - when she stopped starting, I tracked down the problem to a plugged-up fuel lift
pump, with no filter before it?? I rebuilt the lift
pump, added a second filter and rerouted the fuel
lines. She started!
When I went to move further, with the "repaired" engine, I made it about a kilometer before there were alarms and smoke, and I found I had overheated and burned out the exhaust
line and burnt a hole in the new watertrap.
I got a new water trap, and examined the problem - water clearly isn't reaching the exhaust
. So, I got a new exhaust elbow
, replaced the impeller, and verified that the water flowed through - it was flowing well, the water trap was filling (and exhausting), and so I reassembled and moved on.
I made it another kilometer, but then there was smoke and alarms again - I had burned yet another hole in my exhaust - at least I caught it this time before it burned out the water trap! The only thing I can think of is that perhaps once the thermostats kick in, they're blocked somehow? I changed out the thermostats - they were corroded but seemed to open when I dropped them in hot water, though they never quite closed completely. I also changed the zincs, which were completely gone.
(in between here, I also did a lot of other neglected routine maintenance
- changed the oil
, changed the oil filter
, new air filter, new fuel filter
elements, etc - the basics.)
I haven't tested hard since changing the thermostats, but I have a hypothesis - I think that the block is getting too hot, and the white smoke is steam from the little water that is getting through boiling. I think that this could be caused by calcium scale building up in the block, preventing water from flowing through properly, especially with thermostats that were only partially working. I have done a bunch of googling, and apparently my options to get rid of calcium and rust buildup in the block are to either use muriatic acid - which I would prefer not to, given the nasty, toxic nature of the stuff! - or a less-harmful boiler descaler like Marsolve or Rydlyme.
I have not been able to find Marsolve or Rydlyme locally, so currently my next step is to purchase
a large bottle (or two) of C-L-R, which I think will do the trick. After this, I intend to flush the block out completely with fresh water, reinstall the newly-rebuilt fresh water pump, drain the block and reinstall the cooling
loop with the unused heat exchangers.
Before I run out and buy the C-L-R, does anyone know what the total coolant
capacity of the Yanmar
3HM is? Has anyone had experience with using C-L-R to clean out calcium buildup in an engine block?
Any comments otherwise? Does what I am doing sound reasonable? This is my first engine, ever - up until this year the closest thing I've done to any of this is checking the oil
on my dad's old Buick... I'm gaining confidence, but I'd definitely like to hear some more opinions...