Suzuki dt65 overheating/cooling issues&water pressure

[tank187]

HI THERE

Im new to this and was wondering if i can get some help or the right answers,

I just bought a half cabin piranha with a suzuki 65hp oil injected engine which i think is a mid 90s model.
it was only trickling water out from the top pee hole and alarm was always sounding. got a mobile marine mechanic to have a look at it so this is what his done.

changed the impeller and flushed engine while the bottom shaft was down with a garden hose, then put shaft back on
and open up the thermostat cover to relise there was no thermostat there. anyway kept flushing motor out with thermo cover off and motor on idle while also blowing high pressure air thru pee hole, and getting all the sand and salt out as much as he could. now when motor starts up the water takes forever to reach the top and squirt back out with my ear muffs or in a tub. but when he used his muffs the water came thru with in 5 seconds and with good pressure.

the issue im having now is that when the water eventually gets flowing thru, my alarm starts going off and i notice that the head and exhaust start to heat to the point that i cant touch it, but when i rev the motor back up round 4000rpm it starts to cool down. so mainly overheating on idle and not bringing up enough pressure with my muffs that i have just bought new.

i wont ask could it be this or could it be that..... im praying that some one on this site has over come an issue like this and can help me out cause it driving me crazy!

thanx people......

 

[99yam40]

Re: Suzuki dt65 overheating/cooling issues&water pressure

I always replace water pump with the kit not just the impeller as the cup and wear plate get grooved and will not seal off well.

Thermostats need to be in place to regulate the temp and to put some back pressure in system to force cooling water to all parts of the motor at the proper rate to cool properly. May end up with cold spots and hot spots with it removed.

Not sure if that motor has a PRV(poppit valve), but if it does and it is stuck open it will dump water at low RPM and not let block fill all the way up causing hot areas where water in not in cooling passages

 

[tank187]

Re: Suzuki dt65 overheating/cooling issues&water pressure

thanx 99yam40

im going to take your advise and get the whole impeller kit replaced tomorrow and also replace the thermostat.

so on that note will the engine over heat if there is no thermostat at all?

im not sure if it does or dosnt have that poppit valve you mentioned but now im really keen to find out. im just not sure on where to locate it on the engine or what it looks like.

thanx for your kind reply anyway, its nice to know there are people out there who can take the time to reply and help others out. much appreciated...

 

[99yam40]

Re: Suzuki dt65 overheating/cooling issues&water pressure

as I said all water cooled motors need the restriction of a stat or something else to force cooling to proper places, without it there will be hot and cold spots and the fuel will not burn at optimal like it was designed if all of motor is not at proper temp at all times.

Will it cause over heat alarm to come in? Maybe ,maybe not
Seems like I remember reading that some Suzuki's used a float type of device looking at water level in block also for over heat warning. It would detect not enough water in block

Not sure about Suzuki but the Yamaha kits do not include the plastic housing the cup sits in, so inspect it well for signs of melting and replace if you see any

If he was getting a bunch of sand and salt / corrosion out when flushing, there could be some passages plugged up causing hot spots that may need to remove covers to clean properly. Especially on motors run in salt water and not getting flushed with fresh water after

 

[tank187]

Re: Suzuki dt65 overheating/cooling issues&water pressure

just before i start taking things off the motor i thought id ask on your opinion on using a product like salt away or even maybe water mixed with vinegar "as iv heard from other people flushing" if you think that i can clear the salt or corrosion in the passages with them products first before going through that headache.....

and i dont get why the mechanics muffs worked the water thru and had no alarm or overheating compared to the brand new muffs i have that are a perfect fit..... just dont make scence to me. any way thanks again and any help or stuff you suggest is a great help.

 

[99yam40]

Re: Suzuki dt65 overheating/cooling issues&water pressure

I have read that there are cleaning products that clean heat exchangers and motors.
Have to circulate, catch, and recirculate the product mixed with water through motor for a period of time.
Some sounded like they worked,
not sure if vinegar would do much and saltaway could be something for preventaive, but not sure about cleaning corrosion.
But have heard some faily good things about it cleaning salt out

Are the muffs the same design and feed water from both sides?
Is the water pressure and hose size and length the same as his?

 

[tank187]

Re: Suzuki dt65 overheating/cooling issues&water pressure

yep using the same garden hose and as for the muffs they are both the ones that feed the water through both passages, but the only difference with my ones are the framing around them isnt as thick as the frame around his muffs.

if you know any of the names of them products you were reading about, throw them over and il give them a go aswell.

 

[99yam40]

Re: Suzuki dt65 overheating/cooling issues&water pressure

Took me a while to find it again, but here it is and I sent you a PM to the post I read about it in

Rydlyme marine flush

 

[tank187]

Re: Suzuki dt65 overheating/cooling issues&water pressure

thanx alot for that il definitely give it a go and let you know if my problem is solved. thanx so much for your time

 

[hsdtech]

Re: Suzuki dt65 overheating/cooling issues&water pressure

Before you start spending a bunch of $$$, run the motor in a TUB or garbage can full of water and see if you are having the same problem.

 

[tank187]

Re: Suzuki dt65 overheating/cooling issues&water pressure

hey there people, i ran it in a tub of water and also all of the above suggestions. we found that under the power head where the wash plates are were all corroded and blocked with sand and salt, thats why it would pump water good when reving it but not enough flow to keep it cool on idle.

so i returned the boat to the original owner, got my money back and put a grand on top and got myself a johnson 90hp v4 that absolutely rockets me out of the water. its on the back of a 16ft monark runabout and the power is actually more then i need.

but thanks alot to the people who took some time to help me out. lesson well learned.