Monday, August 3, 2009

Engine still overheats and bad news from work.

This weekend didn't go too well. Well, it didn't start well either. On Friday I was cut to part-time at work, effectively reducing my salary by 20%. Thats all the money I had to save and spend on the boat. I will be just making the payments and insurance now, but money for refitting is severely limited now. I've said many times that as long as my job holds up, I should be on target for everything boat related. This will be a set back for sure, but temporary at most.

As for this weekend on the boat, I'll let this post I made on Sailnet describe it. I am stuck on the engine problem still:

I recently purchased a 1975 Downeaster 38' Cutter, re-powered in 1994 with a Yanmar 4JH2E. It only has about 900 hours on the engine, but has been sitting unused for a few years now. I live in Orlando, FL but the boat is in Inglis, FL near Crystal River in the Big Bend area at the sellers dock. He is being kind enough to let me keep it there until I get it in shape to take it elsewhere. So I am limited to making weekend trips up there for now.

When we did the sea trial, the engine performed just fine. We ran it up and down the river for almost 3 hours with no problems at all. I had not taken her out since then (about a month) and have just been doing a lot of cleaning and work replacing the running rigging. Two weekends ago I decided it was time to take her out on the river (its on the Withlacoochee River) and show some friends a good time. Before we went out, I checked all fluids, cleaned out the raw water strainer and topped off the coolant. I noticed there was no rubber gasket or anything on the cap of the raw water strainer, just a metal plate. I didnt think much of it at the time, but now I wonder if there should be one.

The engine ran just fine for about an hour up the river. At one point, I revved it up to 2,800 rpms to see how it responded at cruising speed. Soon after my heart sank as I noticed steam (of course I first thought it was smoke and we were burning down) gushing out of the engine room. I quickly shut it off and had to release the anchor for the first time on the boat (something I needed to learn soon, but in less stressful circumstances).

The cap on the expansion tank for the cooling system had popped off and the cooling water was steaming everywhere. I also noticed that the air silencer had popped off and was hanging by a hose. I had checked it before we left and may have not secured it correctly. So I topped off lost coolant and let the engine rest for a while.

It was getting dark soon and we needed to get back. The engine cranked up just fine but after a short while the temperature was running high. Right before we got to the dock the cap on the expansion tank popped off and once again steam goes everywhere.

We had to go back to Orlando for the week so I did some research and stupidly realized that I didn't check if water was flowing out of the exhaust at all. I had also remembered that the belt was pretty loose, so those were first on the list to check when I came back. I would make sure to double check how I closed the water strainer.

So I go back to the boat this previous weekend. I tighten the belt after much hassle and checked to make sure the raw water strainer is tightly sealed. I then started the engine and first checked to see if any water was coming through the exhaust....none . So my guess is that the problem lies in the raw water circuit somewhere, correct?

I planned on checking and replacing the impeller, of which the previous owner already had a new spare. I soon realized that the impeller is in a hellish place where I can only fit one arm with barely enough room to move a tool. Removing the cover plate for the impeller was tricky, but I did it without loosing my cool. Then I realized that I would not be able to take the impeller out with any ease. I hoped to use the 2 screwdriver method to pry it out, but there was no way I could get two of them in there. I spent the majority of my day getting frustrated over figuring out how to get the impeller out, and didn't get much else done.

The only other thing I checked was to make sure there was nothing blocking the through-hull. I popped the inlet hose from the raw water strainer and was able to suck water through, so that was clear at least.

After leaving my dad asked if I checked to make sure the impeller was even turning after the engine was, I didn't check .

The boat is old, but the engine is the one thing I was happy to have working fine. This completely has left me in the dumps emotionally, and then to cap it off I got cut to part-time at work this week amidst a bunch of lay-offs. Im lucky I still have the job, but loosing 20% of my salary takes away the extra money I was using each month to get the boat in shape.

So that is where I am. What steps should I take this weekend while I am there? I assume to make sure the impeller is even turning by running the engine with the cover off? Do I start to just pull hoses at various points along the circuit to see if water is flowing? Am I limited to buying an impeller puller or is there a cheaper tool I don't know about?

Any help isolating the problem would be appreciated. I hope I can get this done without paying someone to come out to the boat. I am willing to learn and do the hard work, but need some sage wisdom.



Anonymous said...

you might see if you can remove the raw water pump altogether, then you have easy access to it. my boat came with an entire pump rebuilt kit, with bearings, seals, impeller, etc. - it might not be just the impeller that's bad. also, if you happen to notice pieces of the impeller broken off, it's possible these pieces got pushed "downstream" and are clogging water flow, they will sometimes clog water flow in the heat exchanger. the HE should have endcaps which can be removed for the purpose of cleaning out. the belt is the other obvious cause. on this last trip were you able to notice if the belt had enough tension on it to spin the raw water pump, or was the pump spinning and not pumping water?

Larry Klaas said...

From your post it seems virtually certain the problem is your impeller. Most likely it's shed a number of vanes and needs replacement. But as the previous post noted, you'll also need to fish out any broken vanes from the heat exchanger downstream. If you're lucky, any broken vanes may be lodged inside the raw water pump housing and can be cleaned out when you pull the old impeller. First thing I look at when considering the purchase a boat is engine access, particularly to service points such as oil filter, fuel filters, and raw water pump. Ease of access to these areas is critical to proper maintenance. BTW your raw water strainer may not need a rubber gasket. If it doesn't leak when torqued down, you're OK. Good luck!

Anonymous said...

We had a similar problem on a universal engine in a downeaster 38.. every time we pushed the rpm's to far, output of water out the exhaust would decrease and it would overheat.... what was happening was that we were getting air in the system at the strainer. It sounds like the same strainer unit you have. metal brass one with no o ring in it... I'm not sure that's how it came but we ended up removing it from the system to fix the issue. I think. It's been a year or two since it happened.

anyway it would run ok at low rpm but as the vacuum from the impeller increased it would pull more and more air till it air locked and no water was coming out at all.

scott at scottcarle dot com

Erick said...

Hmmm thats interesting about the water strainer letting air in. I was worried something like that may have happened. Thanks for all of the comments.