2015 DF15 overheating issue

[Moonlighter]

If it continues to overheat, as Murray said earlier it would probably be well worth doing a vinegar flush. There is a thread on this forum on whats involved, I will do a search see if I can find it for you.

But next step if it was mine is to clean that gunk out as much as possible, then take it for a run, warm it up then give it a good hard run. If it goes good, keep it going hard for as long as you can to try to get as much fresh water pushing thru those water passages as you can.

[Moonlighter]

Here is the original vinegar flush thread from ThT

https://www.thehulltruth.com/boating...m-vinegar.html

[MasterSchwag]

Is this correct? I dumped about a gallon of vinegar with water into the bucket and just ran at idle for about 30 minutes. The water got slightly warm but never hot. Ill take it out tomorrow to see if it still overheats. Just wanted to make sure I was doing it right. Would anyone assume that water is not going through the engine? Cause I still have no idea lol

[Murray]

Can’t tell since the discharge would be coming out the exhaust which is submerged. Try muffs and you should see water coming from the inside of the prop. When running in a pail your water pump should be completely submerged, looks like your close but a taller pail wouldn’t hurt. With that little volume of water I would have thought the water would have gotten quite hot after 30 minutes but can’t say for sure since I don’t own a a small outboard. If water wasn’t getting through the block you would have gotten a warning with the red light. It’s time to go back and read Moonlighters post #16.

[MasterSchwag]

Can’t tell since the discharge would be coming out the exhaust which is submerged. Try muffs and you should see water coming from the inside of the prop. When running in a pail your water pump should be completely submerged, looks like your close but a taller pail wouldn’t hurt. With that little volume of water I would have thought the water would have gotten quite hot after 30 minutes but can’t say for sure since I don’t own a a small outboard. If water wasn’t getting through the block you would have gotten a warning with the red light. It’s time to go back and read Moonlighters post #16.

So how do I know water is actually going through the motor properly? And I know I need a bigger bucket to put the motor in, I had to improvise til I can buy ear muffs this friday! I will also buy salt away and the ear muff adapter so I can give it another proper flush.

[Murray]

You idle for 30 minutes and don’t seize an engine, get no alarms, I’ll go out on a limb and assume water is circulating. You are worrying too much about internal corrosion, your state on your first post low hours, corrosion takes more than 20 hours to build up. The only sure fire way to test if you have adequate circulation/cooling is to road test that bad boy which brings you back to post #16. If it fails the road test then try salt away. Getting the muffs would be a good idea for future flushes and maintenance.

[MasterSchwag]

You idle for 30 minutes and don’t seize an engine, get no alarms, I’ll go out on a limb and assume water is circulating. You are worrying too much about internal corrosion, your state on your first post low hours, corrosion takes more than 20 hours to build up. The only sure fire way to test if you have adequate circulation/cooling is to road test that bad boy which brings you back to post #16. If it fails the road test then try salt away. Getting the muffs would be a good idea for future flushes and maintenance.

Thank u so much for guiding me my friend! I wasn't concerned with water circulation until I saw inside the thermostat. I had no idea what was in there and it scared me lol. I dont have good luck so I assume the worst! Im gonna take it out asap and test, so Ill be back with something to post in a cpl days!

[MasterSchwag]

Small update: After changing the thermostat, impeller and temperature sensor as well as a small vinegar flush, this engine STILL OVERHEATED! Im totally stumped at this point... Im afraid its a clog somewhere and I have no idea where! I started salt away treatments today but im using a 20 gallon garbage can and im not sure Im doing it right! The first time I tried I added salt away solution to the 20 gallon can before adding water and dont think I had enough water in the can although it spit suds out of the pee hole. The second time I tried, I added the water first and then the solution but the solution never built up suds, so Im not sure it was fully circulating. Both times I ran in neutral and not in gear so Im not sure if that makes a difference. I think I need to run the salt solution a few more times but not sure its even working yet. I have a laser temperature checker so I can see how hot the block is while its running but again im not sure where to check temps at? Anyway Im going nuts learning an expensive lesson here but still am hesitant to take it to the expensive people!

[Murray]

https://www.boats.net/catalog/suzuki...001/water-pump

All I can think of is the bushings 8 and/or 9 are dislodged or not aligned with the water tube so some of the water is not being fed into the engine. When you replaced the water pump did you have a look up into the leg see if all was good? As far as the salt away goes I can’t offer much for advice other than follow the manufacturers instructions, my boating is all fresh water. Running in neutral is safer although it shouldn’t matter. Remember you need to run the engine long enough for the thermostat to open. Other than the water tube or corrosion I can’t of anything else it might be and with a lower hour engine I’m suspicious about corrosion but since I don’t boat in salt water I have no idea how long it takes to build up

[Solarman]

I would think about cleaning/replacing the by-pass valve, it may be stuck open, allowing too much water to go back to the prop?

Just a thought.

[MasterSchwag]

https://www.boats.net/catalog/suzuki...001/water-pump

All I can think of is the bushings 8 and/or 9 are dislodged or not aligned with the water tube so some of the water is not being fed into the engine. When you replaced the water pump did you have a look up into the leg see if all was good? As far as the salt away goes I can’t offer much for advice other than follow the manufacturers instructions, my boating is all fresh water. Running in neutral is safer although it shouldn’t matter. Remember you need to run the engine long enough for the thermostat to open. Other than the water tube or corrosion I can’t of anything else it might be and with a lower hour engine I’m suspicious about corrosion but since I don’t boat in salt water I have no idea how long it takes to build up

Water seems to be streaming down from the area near which you mention these bushings are in. I will take apart the water pump and check to see if it may be an issue. I know its a lower hour engine but its over 5 years old now, and if the previous owner ran it for 20 hours in the dirt and salt water but never cleaned it properly than it may be a clog of some sort. Im the 2nd owner but the original owner never used muffs and ran it only in mud and saltwater. The only thing that actually needed replaced was the impeller on this motor, I believe the temp sensor and thermostat where still in great condition. I do suspect water isnt going all the way though the motor, and this bushing area may be the problem. If it isnt aligned properly, than water should come back down and leak down the side? I didnt look inside to see up there but will do that asap!

[Murray]

ReRead Moonlighters post #25, I forgot all about the by pass valve, there is a good chance it could have the same crud that was in the thermostat. I would go that route before I tore into the water pump again.

[Moonlighter]

You should ALWAYS do a full water pump kit, not just an impeller. A slight, unnoticeable imperfection in the housing/backing plate can cause issues.

[MasterSchwag]

So I went back and took apart the water pump and did the gaskets and metal plate this time because I "thought" they looked fine when I did the impeller! Im an idiot for not doing it before! I also took the lower engine covers off to find the poppet valve or water pressure valve (which I never found) when I noticed a tube coming from the water pump and going to the motor had a slit in it and was leaking lots of water! I cut a half inch off it and put it back on. The water pressure from the pee hole went up a little but temps on the back of the block still reached 160 ish @idle and Im not sure if thats hot or not? Maybe this was a big part of the problem? Either way, now I need to find the water pressure valve and check it! Its just really hard to find info about small outboard engines, especially df15's...

[Murray]

A genuine Suzuki Service manual will have all the information you will need. My water pressure valve in on the mid unit just above the engine oil drain plug, yours may be different? According the the parts page your thermostat is 50C(122F) but I can’t tell you how that would translate to the block. Did you get an overheat alarm? This hose you are talking about not sure what you are talking about? Part #7?

https://www.boats.net/catalog/suzuki...001/water-pump

You should have a flush port on the mid unit. Did you try flushing with a garden hose WITH THE ENGINE OFF?