I pulled the Vetus anti-siphon vent off our 3ym30 to clean the valve and found a failure to follow manufacturer installation instructions that restricted water flow through the valve. The Vetus accommodates several hose diameters if the installer first trims off the smaller diameters of nipple (see page 3 of attached). They trimmed off the 1/2 diameter nipple to accommodate 3/4 in hose, but didn't trim at the very base of the 19mm barb as shown in the instructions. This left part of the 1/2 nipple with it's slightly less than 3/8 dia hole. Retrimming to the bottom of the 19mm barb opened the nipple to a bit over 1/2 in diameter. That is a significant increase in flow for an engine already sensitive to overheating.
Potential Reason for Occasional Overheating of Yanmar 3YM30
- Thread starter Dan_Y
- Start date
I am replacing the thermostat as well, and there is only one choice for opening temp. I pulled the heat exchanger to fix a slow leak of engine coolant and figured I might as well send it out to be descaled and reassembled and pressure tested (fresh water side and raw water side). I upsized the raw water strainer and have a new raw water impeller and cover. Amazing how much raw water flow you can loose when the cover becomes warn! I replaced the mixing elbow as well. It had about 750 hours on it and looked pretty clean until I compared it to a new one. Engine cooling system should be happy this season.
How much water coming out the exhaust take off front round cape on the front heat exchanger only uses O ring and look into heat exchanger holes and run round rod into each hole if looks dirty,also check hose from strainer to raw water pump and I just changed mine.
I added temp gauge into hose going into thermostat and really helps let me know how hot engine running and keep track what’s normal or not mine runs 180 and goes 190 when I push over 3000 rpm’s,I will be changing the antifreeze soon but I don’t really over heat.
My 2007 3 YM.
Nick
I added temp gauge into hose going into thermostat and really helps let me know how hot engine running and keep track what’s normal or not mine runs 180 and goes 190 when I push over 3000 rpm’s,I will be changing the antifreeze soon but I don’t really over heat.
My 2007 3 YM.
Nick
The sensor was a little tricky and tried 2 until the right one worked
I think got the sensor from west marine or marine store to fit in brass tee and gauge all worked with good ground.
I just had back surgery and 4 days in hospital and can’t get around
too much but will look and see for a photo I have some place and I put gauge where key is and just right room and always can see from helm,best thing I ever added.
Nick
I think got the sensor from west marine or marine store to fit in brass tee and gauge all worked with good ground.
I just had back surgery and 4 days in hospital and can’t get around
too much but will look and see for a photo I have some place and I put gauge where key is and just right room and always can see from helm,best thing I ever added.
Nick
Here is photo and may not 3YM but no matter and use
A regular brass tee and may need to run ground wire from tee to ground if not working.
Nick
A regular brass tee and may need to run ground wire from tee to ground if not working.
Nick
Attachments
Thanks Nick. That's a nice installation. Was the bottom of the tee that fastens into the engine a 3/8 npt pipe thread or a metric thread? The parts manual seems to imply 3/8-in npt, but that seems odd on an otherwise metric engine.
PS, I hope you have a speedy recovery!
PS, I hope you have a speedy recovery!
I got the brass fitting at AC hardware and not sure what size but maybe 1/2/and took fittings with me to match up.
Nick
Nick