Suzuki DT4 Cooling Problem

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Brent1961

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Aug 9, 2010
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I replaced the impeller and gaskets, I ran a wire up through all the possible inlets and outlets but I am still not getting continuous flow out of the 'pee" hole. When it is in neutral it will "pee" but when I put it in gear it slowly stops and the engine gets hot, spewing steam and than stopping. Also, I have exhaust coming out the pee hole and not the bottom of the motor. Where the viewing rubber plug is it seems to be bubbling water also. This model (1997) does not have a thermostat so that is not a possibility. I am at a loss for what to do. Please help. Thanks,
 

Brent1961

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Re: Suzuki DT4 Cooling Problem

Both steam and exhaust is coming out of a pee hole. The motor is in the water off the back of my boat so the water level or volume should not be an issue. Shouldn't the exhaust be coming out below the propellor?
 

keith-uk

Petty Officer 3rd Class
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Oct 26, 2008
Messages
94
Re: Suzuki DT4 Cooling Problem

It sounds like you have a buildup or blockage in the exhaust system (leg), or a leaking head gasket.
Exhaust output below the water line just above the prop.
 

Tom @ Buzzard Bluff

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Apr 7, 2010
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Re: Suzuki DT4 Cooling Problem

Have you or anyone changed the impeller recently?
I've heard of similar symptoms when the impeller drive pin was left out. Enough drag between shaft & impeller to pump a bit at idle but when running faster the driveshaft just spins in the impeller due to the increased load.
Grasping at straws but might be worth checking.
 

Brent1961

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Re: Suzuki DT4 Cooling Problem

Thanks for the help. How substantial is it to change the head gasket on this small motor? Also where would be the most likely place to look for a clog?
 

Brent1961

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Re: Suzuki DT4 Cooling Problem

So, I went as far as taking the engine off the lower unit and checked my water pipe from the bottom to the top and it looks ok. The grommet at the bottom that attaches to the lower unit is warped and does not look like it would do much good. The plastic guide that aligns it was broke so it might not have been centered on the lower unit but I was still getting a substantial amount of water flow when in idle and sometimes when in engaged. I took the head off to check the gasket. What specifically should I be should I be looking for inside the head to see if it was a gasket leak or something more substantial? By the way what is the easiest way to remove broken off bolts? Thanks.
 

keith-uk

Petty Officer 3rd Class
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Oct 26, 2008
Messages
94
Re: Suzuki DT4 Cooling Problem

If you have any bolt showing then use a stud remover, if not a center punch and drill, slowly, I have never liked using easy-outs, but that would be up to you.
If you are getting exhaust out of your pee-hole then its a gasket leak or pipe joint leak.
 

squidwood

Cadet
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Apr 11, 2010
Messages
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Re: Suzuki DT4 Cooling Problem

Hi,

I have the same engine and had a similar problem with the water pump and the engine not pumping water as good as it should, so this is what i did.

i changed the impellor as i knew it would need one as very little water came out the 'pee' hole, but when i put it back together and ran the engine it pumped a good amount of water for about 5 minutes and then stop.

so i took the bottom leg off again and blew through the water tube (i put a piece of fuel pipe on the end of it) and found that air was exiting somewhere in the leg rather that through the 'pee' hole, so i rang a marine shop to see what this could be.

After speaking with their mechanic i took it in for them too look at it,

while i was in the shop they did the same thing then they remaved a big slotted bolt at the front of the engine and air came out!! he then told me that the water tubes that go round the engine are blocked and will need to be cleaned out!!

so i left it with them and two weeks later i got a phone call, they told me that there was a crack in the block and as the engine got warm the crack opened and the water exited through the crack rather than through the 'pee' hole, so i assumed the engine was now broke as the cost to repair it would out weigh the value of the engine, luckily they only charged me for the gaskets and not labour so my bill was only ?30 rather than the quoted ?120.

anyway when i got the engine home i ran it in my bucket of water, 15 minutes later and it was still pumping water, 30 minutes and still pumping water, so i took it out up the river and two hours of running she was still pumping water.

Anyway if you blow in the water tube that might give you an indication of where the water is going, plus by removing the big slotted bolt will tell you if the water tubes around the engine are blocked, the slotted bolt is look at the engine with the prop facing you, follow the leg up and its in the center of the engine at the top, just under the power head, if i havnt explained it well enough then i will add a picture of it.

let me know how you get on,

Dave
 

carakatus

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Joined
Sep 20, 2010
Messages
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Re: Suzuki DT4 Cooling Problem

SUZUKI DT4 COOLING SOLVED...I had the same problem with cooling on my 1989 suzuki dt4. It had sat for 6 years..but looks almost new..FOUND OUT it was the seal ..part no. 09289-10002 (oil seal) that sits on the pump housing for the drive shaft. The seal was worn just enough so water would be pumped out between the driveshaft and seal as well as the pump outlet. It is right next to the pump outlet so when I tested it with a drill spinning the driveshaft water flowed over it from the pump so it was hard to tell it was leaking ...tilting the leg so water coming from the pump flowed away from (oil seal) revealed the water leak. (not very much) but.. The pump outlet pushed out most of the water but none the less water did leak past the shaft seal..I believe enough water leaked pass the seal making pump water pressure weaker then exhaust pressure and stopped flow to the head.
Previously I had changed the impeller, gaskets.. cleaned out all passageways after removing the powerhead..and still had same little or no water to head..none or very little pissing.. and if I added throttle it started spittin and only steam came out... Changing the seal solved the cooling issue for me.. Now there is a constant flow from the pisser...Works great at all speeds now and head stays cool..

New News......Well Spoke to soon...the problem returned...still intermittent cooling...seems to be better with the shift link connector cover off..but still peters out ..turning to steam..when throttling up...
So.. I decided to rework the cooling path and eliminate any exhaust pressure which seemed to be stopping water flow. Possibly back flowing exhaust pressure into the water jacket surrounding the cylinder.. thus stopping water flow. The water pump seems to work great. Tested it with engine running but waterpump connected to a tube exiting the leg..suprised at the amount of flow.. During this test I had a water hose attached to the powerhead to keep the engine cool. So..I took the powerhead off, sealed up any water flow exiting to the exhaust leg, rerouted the bearing cooler drain to drain outside the exhaust chamber(leg) using a copper tube...now exhaust pressure has no effect on water pump pressure...Seems to work well, the pump puts water through the head at a nice flow, really nice.. as well as water exiting the copper drain tube for the bearing cooler...Ran motor for a while at various speeds and seems to be fine...flow starts immediately and increases as i throttle up...like I think it should.. now water no longer drains out, and down the inner exhaust leg..but has to exit the two drains, the tell tale hole and the copper drain tube for the bearing cooler, both exit outside of the exhaust leg so there is no back pressure to deal with... Will test soon in the water on my boat to see results...
There must be a reason the cooling problem is happening, as all ports are clear... may be a crack somewhere, an exhaust leak into water jacket.. maybe the powerhead is warped causing exhaust pressure to enter the water jacket overcoming the water pump pressure...??? anyway I cant find it...but this seems to be working...
but this seems to work...for now..
 
Last edited:

weavoid

Recruit
Joined
Jul 14, 2014
Messages
1
Just to say I had the same problem with my 1988 DT4 two stroke Suzuki.
Problem was no cooling water circulation / no water coming out of the tell tale
Inspected the pump assembly and discovered a groove worn in the wear plate and also the pump body.
Replaced the wear plate and impeller, reassembled pump and ran with drill attached to drive shaft in bucket of water. Pump action still pathetic.
Attached a length of small clear hose (the type fitted to your windscreen washers, can purchase easily) length approximately the same height as engine block.
Ran pump with drill attached, as above in bucket of water to discover the water only rising about 5 or 6 inches up the clear tube so plainly not enough head to reach engine block.
Stripped down the pump again and decided to get rid of the groove worn in the pump body, this I did by mounting the pump body in a four jaw chuck in my lathe and
after carefully clocking up the main inside bore and front face proceeded to machine 0.15mm from the 'grooved' face and so re-established a flat face and then
machined the same amount from the front face to maintain the correct depth for the impeller. Finished off with a bit of fine emery so everything inside is nice
and smooth and shiny.
Reassembled the pump with some petroleum jelly, ran with drill in bucket of water and problem totally solved, pumps like a dream.
 

Stevan72

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Joined
Dec 21, 2020
Messages
2
Re: Suzuki DT4 Cooling Problem

SUZUKI DT4 COOLING SOLVED...I had the same problem with cooling on my 1989 suzuki dt4. It had sat for 6 years..but looks almost new..FOUND OUT it was the seal ..part no. 09289-10002 (oil seal) that sits on the pump housing for the drive shaft. The seal was worn just enough so water would be pumped out between the driveshaft and seal as well as the pump outlet. It is right next to the pump outlet so when I tested it with a drill spinning the driveshaft water flowed over it from the pump so it was hard to tell it was leaking ...tilting the leg so water coming from the pump flowed away from (oil seal) revealed the water leak. (not very much) but.. The pump outlet pushed out most of the water but none the less water did leak past the shaft seal..I believe enough water leaked pass the seal making pump water pressure weaker then exhaust pressure and stopped flow to the head.
Previously I had changed the impeller, gaskets.. cleaned out all passageways after removing the powerhead..and still had same little or no water to head..none or very little pissing.. and if I added throttle it started spittin and only steam came out... Changing the seal solved the cooling issue for me.. Now there is a constant flow from the pisser...Works great at all speeds now and head stays cool..

New News......Well Spoke to soon...the problem returned...still intermittent cooling...seems to be better with the shift link connector cover off..but still peters out ..turning to steam..when throttling up...
So.. I decided to rework the cooling path and eliminate any exhaust pressure which seemed to be stopping water flow. Possibly back flowing exhaust pressure into the water jacket surrounding the cylinder.. thus stopping water flow. The water pump seems to work great. Tested it with engine running but waterpump connected to a tube exiting the leg..suprised at the amount of flow.. During this test I had a water hose attached to the powerhead to keep the engine cool. So..I took the powerhead off, sealed up any water flow exiting to the exhaust leg, rerouted the bearing cooler drain to drain outside the exhaust chamber(leg) using a copper tube...now exhaust pressure has no effect on water pump pressure...Seems to work well, the pump puts water through the head at a nice flow, really nice.. as well as water exiting the copper drain tube for the bearing cooler...Ran motor for a while at various speeds and seems to be fine...flow starts immediately and increases as i throttle up...like I think it should.. now water no longer drains out, and down the inner exhaust leg..but has to exit the two drains, the tell tale hole and the copper drain tube for the bearing cooler, both exit outside of the exhaust leg so there is no back pressure to deal with... Will test soon in the water on my boat to see results...
There must be a reason the cooling problem is happening, as all ports are clear... may be a crack somewhere, an exhaust leak into water jacket.. maybe the powerhead is warped causing exhaust pressure to enter the water jacket overcoming the water pump pressure...??? anyway I cant find it...but this seems to be working...
but this seems to work...for now..
So did it worked..? I have the same problem in present time.. What should I do..??
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Are these examples from motors used in saltwater ? Does the motor have a flushing port around the powerhead or under the pan, if so will need a flush adapter, connect a garden hose there and flush with a much higher water pressure as long as you want. Can also flush with compresed air all the water passages.

If the motor doesn't count with a flushing port, remove the lower leg and connect a water hose on the water pick up tube. Is the peeing port built directly on the powerhead or has an internal water hose that squirts water out ?

Happy Boating
 
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