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Hey all, I'm working on my Suzuki DS15a outboard with overheating problems. I think it fits the classic symptoms of what I've been researching: After a few month layup (and not as routine amount of flushes as I should have done) I took it out for the first ride of the season - starts great, telltale water is spraying full strength. Idling out the marina (its on my dinghy) did fine. As I'm revving up off idle a bit, it goes into limp mode with the warning light on solid. Back down to idle for a few minutes and it clears up, light goes out. After trying a few times I disconnect the temp sensor lead and get the expected trouble code but no more going to limp mode - so I know its temperature vs oil pressure.
I replaced the thermostat and internal anode - both looked pretty bad. There was some corrosion behind the water pump but did not look excessive. Either way, the problem persisted. I pulled the thermostat out and problem is still there. I used my IR temp gauge on the cylinders and temps (with no thermostat) were definitely higher than I felt they should be - around 160 - 175 degrees.
So I brought it home, pulled the thermostat housing, pulled the lower unit. Water pump looks like its time for replacement but no vanes broken etc. I fashioned a fitting so I can connect my water hose to the water pump tube. As expected telltale is great, but engine running at idle on the stand cylinders still getting up to the 160 range.
I pull the thermostat cover again. With the hose turned on there is plenty of water to the anode and from there to the hole on the left which comes from the anode cavilty. There is nothing coming up the larger hole where the thermostat sits. I tried plugging the small hole on the left as well as the telltale to build pressure but nothing coming behind the thermostat. I tried a bladder to force water into the larger hole and nothing.
My theory of the way this SHOULD work is that water should be coming through the cylinders and behind the thermostat. Then once the thermostat gets heated up it opens and allows water to pass through and into the smaller hole on the right side of the picture where it exits via the lower unit. I'm not quite sure of the logic of the water coming through the tune to the anode area and then through the foot but assume that's the "bypass" so the water pump can always push water somewhere. In either case there is a small passage at the rear of that larger hole where the thermostat sits and I believe that must be blocked somewhere. I've tried running a wire through it (about 5 inches in) got some salt out but still no flow. I tried pressuring it with a can of carb cleaner with the small straw to see if I could dislodge it but no luck. I currently have CLR in that hole letting that soak - but its been soaking now for about 5 hours and doesn't seem to be having an affect.
My questions to anyone who may have experienced this - it seems to be a common issue on Suzuki 9.9, 15 and 20HP engines:
The engine has 117 hours on it and has been super reliable up to this point. While this may be a design flaw to some extent I take responsibility for not flushing as often as I should have (although I've read folks that do still have this issue after about 3 years or so). Mine is 5 years old so from that perspective I've done well I guess.
I would feel more confident about using the flush if I was getting any flow at all from the thermostat through the powerhead.
Any advice appreciated - do I try the flush or bite the bullet and tear it down for manual cleaning? Or any other thoughts?
Thanks in advance!
I replaced the thermostat and internal anode - both looked pretty bad. There was some corrosion behind the water pump but did not look excessive. Either way, the problem persisted. I pulled the thermostat out and problem is still there. I used my IR temp gauge on the cylinders and temps (with no thermostat) were definitely higher than I felt they should be - around 160 - 175 degrees.
So I brought it home, pulled the thermostat housing, pulled the lower unit. Water pump looks like its time for replacement but no vanes broken etc. I fashioned a fitting so I can connect my water hose to the water pump tube. As expected telltale is great, but engine running at idle on the stand cylinders still getting up to the 160 range.
I pull the thermostat cover again. With the hose turned on there is plenty of water to the anode and from there to the hole on the left which comes from the anode cavilty. There is nothing coming up the larger hole where the thermostat sits. I tried plugging the small hole on the left as well as the telltale to build pressure but nothing coming behind the thermostat. I tried a bladder to force water into the larger hole and nothing.
My theory of the way this SHOULD work is that water should be coming through the cylinders and behind the thermostat. Then once the thermostat gets heated up it opens and allows water to pass through and into the smaller hole on the right side of the picture where it exits via the lower unit. I'm not quite sure of the logic of the water coming through the tune to the anode area and then through the foot but assume that's the "bypass" so the water pump can always push water somewhere. In either case there is a small passage at the rear of that larger hole where the thermostat sits and I believe that must be blocked somewhere. I've tried running a wire through it (about 5 inches in) got some salt out but still no flow. I tried pressuring it with a can of carb cleaner with the small straw to see if I could dislodge it but no luck. I currently have CLR in that hole letting that soak - but its been soaking now for about 5 hours and doesn't seem to be having an affect.
My questions to anyone who may have experienced this - it seems to be a common issue on Suzuki 9.9, 15 and 20HP engines:
- Is my understanding correct about the way it should be working?
- One option I've read about is to put the thermostat housing back on and set up a Rydlyme flushing system which essentially puts a pump in a bucket and pushes a solvent through the water tube and flushes the system - I'm told you let that process run about 4 hours and some folks have had success.
- The only other option I know of is to remove the cylinder head and scrape out the deposits.
The engine has 117 hours on it and has been super reliable up to this point. While this may be a design flaw to some extent I take responsibility for not flushing as often as I should have (although I've read folks that do still have this issue after about 3 years or so). Mine is 5 years old so from that perspective I've done well I guess.
I would feel more confident about using the flush if I was getting any flow at all from the thermostat through the powerhead.
Any advice appreciated - do I try the flush or bite the bullet and tear it down for manual cleaning? Or any other thoughts?
Thanks in advance!