Bought a 1990 Hunter 28 a few years ago to learn to sail and it has had good bones to her, but as one would expect an older boat needs lots of TLC. Last year when I last took it out she overheated. I had just broke the channel and couldn't turn around so I pointed into the wind and hoisted the main, killed the engine to sail a bit to let her cool down to get her in port. I was able to crank the motor back up and putt into port and she alarmed just as I was putting her in the slip so confident no damage was done as she didn't get really hot.
Finally got around to inspecting this spring and sea water pump had no impellers so I replaced it. Wasn't sure of condition of heat exchanger so pulled it from the boat along with the exhaust elbow. I soaked the core in phosphoric acid as it was a bit dirty. Not as bad as I anticipated though. A few tubes were clogged so I cleaned those with a gun barrel brush. Got her put back together with fresh gaskets and seals and threw a new coat of yanmar grey on there to pretty her up.
There was gunk in the coolant overflow so I decided to do a complete flush of the motor and cleaned out the overflow reservoir too. Filled motor with distilled water for the flush. That is where I am at there, will fill with dexos when I get her running good. I also rebuilt my raw water filter as it was not sealing properly any longer with new seals, site glass and some other hardware.
Since I have not done the fuel filter and broke the fuel lines to do all this work, I went ahead and did that too. Replaced primary (there was sludge in the bottom of the filter) and cleaned the housing up good and then did the secondary on the motor. Used gravity with the bleed valve open on first filter to fill it up (made a little mess but no diesel in the bilge).
Lessons learned for sure for next time. lol Used the manual pump to bleed to the secondary fuel filter bleed screw. Didn't take terribly long to fill it up. I probably pumped it for less than a minute so I was a little surprised how quickly it got fuel there. Then I bled the screw that drops down under the fuel filter before it enters the fuel pump. That one had quite a bit of air and spritz out for a bit before I saw a flow. I decided to try it from there hoping no air was beyond the fuel pump. It cranked right up as she always has. I then noticed a huge fuel leak under the motor.
When I removed the fuel line from the manual pump to get the exchanger off, the copper washer fell off, I didn't even see it but found it in the mess of diesel under the motor so I read the Yanmar manual and it says there are 2 washers, one on each side of that nut but I only found one so I put an extra one on according to the yanmar manual. I called my local yanmar service center and they agreed to use 2 washers. I assumed that was where it was leaking so I removed the extra washer on the outside of the bolt (the bolt has a hole in it that fuel passes through and it threads into the manual pump) and tightened down but it still leaked. Then I found it was leaking from before the fuel filter and hugging the fuel line. That nut must have worked loose in all the work and I didn't check before starting the boat. I tightened that nut up and a couple more on the fuel filter and cranked her up and then no more fuel leak.
Inspected the boat to assure the raw water was coming out properly and if the seawater pump was doing well. I saw more throughput than I had ever seen in the past. No visible leaks on the motor that I can observe from anywhere else. My goal then was to let her run a good 30 minute and cycle the distilled water through the motor good so I could drain and add coolant. I realized that I didn't fill the overflow with any coolant and knew the thermostat would be kicking over soon so I pulled the reservoir from the bracket while the motor was running against my better judgement and opened it up and proceeded to fill the reservoir with distilled water. At that point it started sputtering while I was fill it so I stopped and put the cap back and by the time I got the reservoir hung the motor died. I was unable to get the motor started again and in the 100 degree heat decided to call it.
The more I think about it the less I feel like me opening that overflow had anything to do with it dying but I want to throw in that detail because I am learning to work on this motor and am not a mechanic. The motor ran for at least 5 minutes, well under 10. Engine got warm but not hot, I don't think the themostat ever opened because when I opened the reservoir it was still filled up. Then again, maybe I have it completely full of fluid. When it died it sounded like it wasn't getting fuel. I suspect trash in the fuel line or maybe air.
Apologies for the long write up but there has been a lot of work done on the motor since it last ran so I want everyone to know the history of this repair. So my question after this long book is, what is the best place to start in diagnosing this? I live about 1.5 hours from my boat so I have to figure out my strategy before going there unfortunately. I was going to start with seeing if I have fuel at each bleed screw and if missing anywhere go back from that point. If I didn't find anything, I was going to try and see if there is a bleed valve on the fuel pump and then bleed the cylinders but outside of that and doing something drastic like draining the tank of all fuel (it is pretty full) and removing all fuel lines, taking them home and cleaning them. Removing tank and assuring it is clean with no trash, putting in fresh fuel, wasn't sure what to do. My tank is plastic so hopefully there is no trash in it but very likely condensation as I live in a highly humid environment, and it is a sailboat that lives on the water. It is disgusting when I look at it, full of 35 years of dust and stuff. Definitely on the list to clean up. Can't read the gauge to see how much fuel she has. It has definitely been something I wanted to pull but I am also an advocate of not fixing things that aren't broken. That usually leads to me breaking more stuff.
Thanks for listening and I appreciate anyone's advice on getting her running good again.
Finally got around to inspecting this spring and sea water pump had no impellers so I replaced it. Wasn't sure of condition of heat exchanger so pulled it from the boat along with the exhaust elbow. I soaked the core in phosphoric acid as it was a bit dirty. Not as bad as I anticipated though. A few tubes were clogged so I cleaned those with a gun barrel brush. Got her put back together with fresh gaskets and seals and threw a new coat of yanmar grey on there to pretty her up.
There was gunk in the coolant overflow so I decided to do a complete flush of the motor and cleaned out the overflow reservoir too. Filled motor with distilled water for the flush. That is where I am at there, will fill with dexos when I get her running good. I also rebuilt my raw water filter as it was not sealing properly any longer with new seals, site glass and some other hardware.
Since I have not done the fuel filter and broke the fuel lines to do all this work, I went ahead and did that too. Replaced primary (there was sludge in the bottom of the filter) and cleaned the housing up good and then did the secondary on the motor. Used gravity with the bleed valve open on first filter to fill it up (made a little mess but no diesel in the bilge).
Lessons learned for sure for next time. lol Used the manual pump to bleed to the secondary fuel filter bleed screw. Didn't take terribly long to fill it up. I probably pumped it for less than a minute so I was a little surprised how quickly it got fuel there. Then I bled the screw that drops down under the fuel filter before it enters the fuel pump. That one had quite a bit of air and spritz out for a bit before I saw a flow. I decided to try it from there hoping no air was beyond the fuel pump. It cranked right up as she always has. I then noticed a huge fuel leak under the motor.When I removed the fuel line from the manual pump to get the exchanger off, the copper washer fell off, I didn't even see it but found it in the mess of diesel under the motor so I read the Yanmar manual and it says there are 2 washers, one on each side of that nut but I only found one so I put an extra one on according to the yanmar manual. I called my local yanmar service center and they agreed to use 2 washers. I assumed that was where it was leaking so I removed the extra washer on the outside of the bolt (the bolt has a hole in it that fuel passes through and it threads into the manual pump) and tightened down but it still leaked. Then I found it was leaking from before the fuel filter and hugging the fuel line. That nut must have worked loose in all the work and I didn't check before starting the boat. I tightened that nut up and a couple more on the fuel filter and cranked her up and then no more fuel leak.
Inspected the boat to assure the raw water was coming out properly and if the seawater pump was doing well. I saw more throughput than I had ever seen in the past. No visible leaks on the motor that I can observe from anywhere else. My goal then was to let her run a good 30 minute and cycle the distilled water through the motor good so I could drain and add coolant. I realized that I didn't fill the overflow with any coolant and knew the thermostat would be kicking over soon so I pulled the reservoir from the bracket while the motor was running against my better judgement and opened it up and proceeded to fill the reservoir with distilled water. At that point it started sputtering while I was fill it so I stopped and put the cap back and by the time I got the reservoir hung the motor died. I was unable to get the motor started again and in the 100 degree heat decided to call it.
The more I think about it the less I feel like me opening that overflow had anything to do with it dying but I want to throw in that detail because I am learning to work on this motor and am not a mechanic. The motor ran for at least 5 minutes, well under 10. Engine got warm but not hot, I don't think the themostat ever opened because when I opened the reservoir it was still filled up. Then again, maybe I have it completely full of fluid. When it died it sounded like it wasn't getting fuel. I suspect trash in the fuel line or maybe air.
Apologies for the long write up but there has been a lot of work done on the motor since it last ran so I want everyone to know the history of this repair. So my question after this long book is, what is the best place to start in diagnosing this? I live about 1.5 hours from my boat so I have to figure out my strategy before going there unfortunately. I was going to start with seeing if I have fuel at each bleed screw and if missing anywhere go back from that point. If I didn't find anything, I was going to try and see if there is a bleed valve on the fuel pump and then bleed the cylinders but outside of that and doing something drastic like draining the tank of all fuel (it is pretty full) and removing all fuel lines, taking them home and cleaning them. Removing tank and assuring it is clean with no trash, putting in fresh fuel, wasn't sure what to do. My tank is plastic so hopefully there is no trash in it but very likely condensation as I live in a highly humid environment, and it is a sailboat that lives on the water. It is disgusting when I look at it, full of 35 years of dust and stuff. Definitely on the list to clean up. Can't read the gauge to see how much fuel she has. It has definitely been something I wanted to pull but I am also an advocate of not fixing things that aren't broken. That usually leads to me breaking more stuff.
Thanks for listening and I appreciate anyone's advice on getting her running good again.
.