85hp suzuki still overheating

fish4970 · Jun 24, 2003

87' suzuki DT85 overheating & oil injection concerns I have replaced the water pump = good I have pulled & tested the thermostat = good I have pulled the head looking for trash in the water jackets = clean as a whistle I have a verry strong tattle tale but still overheats above 3900 rpm The other day i was just cruising at about 3500 rpm and the motor lost power & died started right back up, but would die about evry 2 minuits the temp was ok, but I am worried about the oil injection. It did not look like it has used very much oil from out of the tank. I had a jug of oil with me / mixed it and motor stoped dying. Is there any way to check or adjust the oil flow sorry about the lenght of the post thanks in advance for any help Signed verry confused fish

Fouled Plug · Jun 24, 2003

Re: 85hp suzuki still overheating

You can make a mark on the oil tank, and compare the amount used to the amount of fuel burned to see if the ratio is about right. I would be concerned if your pre-mix made the symptoms disappear....sounds like you are flirting with disaster if you're not pumping oil.

fish4970 · Jun 24, 2003

Re: 85hp suzuki still overheating

WILL IT HURT TO RUN PREMIX & OIL INJECTION WHAT COUL BE CAUSING THE OVERHEATING THE CYLINDERS LOOK OK TO ME TOP & BOTTOM LOOK BRAND NEW & MIDDLE HAS ONLT ONE VERY MINOR SCRATCH COMPRESSION IS 150-150-155

fish4970 · Jun 24, 2003

Re: 85hp suzuki still overheating

does anyone know the head bolt torque specs.

fish4970 · Jun 24, 2003

Re: 85hp suzuki still overheating

what is the proper plug & gap for this motor thanks

fish4970 · Jul 10, 2003

Re: 85hp suzuki still overheating

new twist i got a pressure guage 0-30# placed the muffs on and got 0# pulled the guage fitting at the head and it looks like air & water coming out of the hole at an idle then just air when i rev it a little i get just water put the guage back in and get 3# at idle bump it to 1800 rpm and get 10# shut it down and scratch my head start it back up and get 0# for 2 minuits all this time i am getting a good idle pee stream where is the air coming from i just replaced the water pump and head gasket trying to find out why it's overheating i'me verry confused jim if you catch this i put the timing light on it just as i mentioned to you and got 27 btdc

fish4970 · Jul 11, 2003

Re: 85hp suzuki still overheating

does anyone know what the water pressure shuld be at idle & wot what shuld the timing be set at

rudeafrican · Jul 11, 2003

Re: 85hp suzuki still overheating

fish, Muffs are not the greatest when testing waterpump and cooling. Run the lower end in a drum filled with water covering the water intake. Your oil situation is still a concern. I would mark the oil level in the oil tank and then run on premix untill I'm sure I'm using the correct volume of oil for the number of litres of fuel used. If the oil injection is working, you wont cause any damage by running too rich. If the oil injection is not working, you have already started the damage. Remember, the oil not only lubes the cylinder walls but all the bearings and crank as well. I also suggest you get a good workshop manual, all the spec will be listed in there. Good luck and report back.

jim dozier · Jul 11, 2003

Re: 85hp suzuki still overheating

Fish you need to get a manual. You are far enough into this that you need one. I will check my manual tonite. I think from memory the head bolt torque was 30-44 ft-lbs. Timing max advance 21.5 deg BTDC. Check water pressure in the water not on muffs. You can verify the oil pump ouput by buying a syringe with ml gradations like they use to measure baby meds (no needle) at a pharmacy. Buy some new oil line hose (there are different diameters) for the section between the oil tank and the oil pump. Replace the oil filter while you are in there. Disconnect the oil tank and run a hose about a foot long from the oil pump up to the open ended (remove the plunger) syringe which is filled with oil. I was able to wedge the oil line in next to the tank so I didn't have to hold it. Disconnect the rod that connects the throttle to the oil pump. At 1500 rpm with the oil pump set at minimum rate, it should pump 2.2-3.7 ml at 5 minutes. At 1500 rpm with the oil pump set at max (there are three marks on the oil pump, this is where a manual is handy) it should pump 5.9 to 8.9 ml at 2 minutes. Fish4970 I am sticking the history on my engine in here so others can see what I have done since we are having the same problem. I am having and have had problems with overheating at WOT on my 1987 Suzuki DT85. I had replaced the oil hoses while I had the powerhead off to replace a leaking engine holder gasket (which is beneath the power head gasket). This engine runs at about 185 degrees F. at 1/2 to 7/8 throttle but at WOT it creeps up to 200+ degrees F. and will set off the alarm (which by the way has been replaced) after 3 or 4 minutes. The engine runs pretty good otherwise. In an effort to fix this I have: 1. Replaced water pump impeller (twice). It overheated quickly when I bought it and replacing the water pump the first time really improved it, but eventually I noticed the WOT problem. 2. Replaced thermostat. Even tried it for a while without thermostat. 3. After consulting a Suzuki mechanic I replaced the head gasket with a newer OEM version and cleaned out the clogs in the head cooling passages. 4. Installed temp gauge. 5. Pulled the powerhead and replaced the exhaust cover gaskets and cleaned exhaust cooling passages. 6. Replaced temp sensor. This seemed to work for a while but the problem either returned or was still there and I just couldn't tell right away. 7. I should have replaced the engine holder gasket the first time I had the powerhead off but one mechanic said I wouldn't have to. He was wrong. 8. My other mechanic asked if I had properly installed the water bypass valve when I had the head off. I did but I am wondering if maybe the spring on the bypass valve is old and the valve is leaking too much at high speed. It is the only thing left in the cooling system that hasn't been replaced. This engine pees like a fire hose and I have I think eliminated every other possibility. I finally got the temp to quit creeping up this week by retarding the ignition 3 degrees at max advance. I was able to blast around at WOT all day without any noticeable (I don't have a tach or speedo) loss in performance.

fish4970 · Jul 11, 2003

Re: 85hp suzuki still overheating

thanks a bunch jim i'll ordered a manual and if i cant figure it out i'll just bite the bullet and take it to the dealer thanks again to all of you especially jim

jim dozier · Jul 11, 2003

Re: 85hp suzuki still overheating

Fish I checked my Clymer manual and edited my post above regarding torque, timing, and oil delivery rate.

fish4970 · Jul 13, 2003

Re: 85hp suzuki still overheating

the saga continues i tried it out today with a water pressure guage and a borrowed high acuracy thermocouple and guage to read the temp at the same location on the head as the temp switch pressure at idle in the lake = 0# pressure at idle with muffs = 2# pressure wot in lake = 7# pressure when throttle quikly bumped with muffs =15 # temp on muffs 125 temp at 3500 rpm on lake 180 temp at 5200 rpm 38 mph 230 timing was changed from 27 BTDC to 20.5 BTDC motor was lowered to lowest position when at the lake i tried just for grins taping three stacked pennies to the max advance bracket and it dropped wot temp 10 degrees the alarm never went off how hot in too hot for this motor what should the water pressure be with a new pump thanks to everyone for all the help so far hope you catch this jim

jim dozier · Jul 14, 2003

Re: 85hp suzuki still overheating

The overheat sensor is set to alarm at 237 deg F. and wont shut off until the temp goes below 194 deg F. I'd say anything under 200 is OK at WOT, clearly you are at the limit, another 7 deg and the alarm will sound and I don't think you want to run at 230 deg F regularly. I don't know what the deal with your water pressure is, you got that thing hooked up correctly? Where are you pulling the pressure from? What is your pee stream doing while you are getting those readings? I can't understand why you are getting more pressure on the muffs than in the water, are you hooking it up to a fire hydrant? Any chance the pickup tube from the impeller isn't seated properly? Your engine sounds alot like my mine except for the water pressure readings. I don't have a pressure gage and the force of my pee stream has never been an issue. Eventually one of us will get this straigtened out and let the other one in on it.

fish4970 · Jul 14, 2003

Re: 85hp suzuki still overheating

jim it's just hooked up to a regular garden hose the pee stream has a small arch to it at idle but above idle, if you turned it sideways it would probably pee 20 feet the pressure guage is hooked up where the small square head plug was in the head between #1&#2 cylinder and yes one of us will figure it out some day if it's me you will be the second to know after my wife she is getting disgusted with me spending so much time trying to figure it out good luck

fish4970 · Jul 16, 2003

Re: 85hp suzuki still overheating

i pick my clymer up tomorro and a new exhaust cover gasket guess i'll take a peek there not much ellse to try that i can think of

sirlespat · Jul 17, 2003

Re: 85hp suzuki still overheating

this could be your problem (my theory is if it gets hard double check the simple things). One problem with the waterpump in your motor is it can be assembled with the lower plate upside down. This puts the hole for water to enter in between the same impeller blades as the hole at the top of the pump resulting in poor pressure, it needs to be placed so the impeller pushes the water from the entry hole at the bottom about 270 degrees around the pump before it can exit through the top hole. the reason I mention this is because the motor will run fine on muffs because the pressure is generated by the water supply, it will pee when in the lake but will overheat at WOT. The only way I know to check this is to take the lower unit off again. Good Luck sirlespat

fish4970 · Jul 19, 2003

Re: 85hp suzuki still overheating

still wondering if anyone has any normal water pressure readings on this 87 dt85

vidar · Jul 19, 2003

Re: 85hp suzuki still overheating

i got a 140hp 85 mod.. got aprox.7psi at idle and 25 at wot.. but you shoud have at least 15 at wot.. 130f at idele and 160-175f at wot...hope this can help..

fish4970 · Jul 20, 2003

Re: 85hp suzuki still overheating

thanks motoraddicted i guess i'll pull the lower unit again and replace both pipe gromets check the pump again pull the head again and replace the relief valve pull the power head and replace mounting gaskets pull the exhaust cover and replace those gaskets buy a new thermostat allthough present one works if all this doesent work any one want to buy this piece of junk that has less than 200hrs on it thanks for all of your help there is no better site than this one for all boaters who need help

jim dozier · Jul 21, 2003

Re: 85hp suzuki still overheating

Fish I was hoping you would replace your bypass valve in your cylinder head before me so I would know if that had any effect. That is the next and last thing on my list but I am busy with my carbs for non overheating issues at the moment. That was an interesting comment by Sirlespat but I don't think that is our problem (I wish it was, it would be a simple fix). I recall that the impeller plate has the word UP stamped on it so I am pretty sure (nothing is certain) that I got it right when I put it on. And it is the second one I've installed.

85hp suzuki still overheating

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