85hp suzuki still overheating

[fish4970]

Re: 85hp suzuki still overheating

Jim I hope to change the bypass valve this weekend<br />I will keep you posted

 

[jim dozier]

Re: 85hp suzuki still overheating

Fish I checked with my mechanic and he says he doesn't think the bypass valve will be the problem. He said as a long shot that the driveshaft bearing housing, which is the large plate that is between the gearcase and the water pump, may be leaking exhaust or air into the high water pickup water passage which starts in front of the trim tab. He said to test this he raises the motor in the water (straight up, not with the tilt/trim) with a lift until the driveshaft bearing housing is above the water (but the cavitation plate is still submerged). If it is leaking the tell tale should diminish as the housing is raised above water. The Suzuki has twin pickups and the high water pickup in front of the trim tab runs through this housing.<br /><br />The fix would be to remove the lower unit and take off the plate and replace the seal between it and the gearcase.<br /><br />Hope this helps. I am going to try and see if I can get my motor into a plastic garbage can and check it this weekend.

 

[sirlespat]

Re: 85hp suzuki still overheating

If the seal between the gearcase and pump was u/s I would expect to see water contamination of gearcase oil. You seem to have many possibilities to consider so see what you can eliminate.<br />1. run temporarily on 50:1 premix but leave oil injection still on this will eliminate oil as a problem (carry some spare plugs)<br />2. Temporarily remove thermostat for troubleshooting<br />The most interesting info I saw in you post was <br />pressure at idle in the lake = 0#<br />pressure at idle with muffs = 2#<br />I think that you should have pressure at idle in the lake. To check for a water tube leak look to the small hole in the front of the leg just above gearcase when running on muffs, if it is leaking water there it is a good chance of poor seal of the watertube. On muffs you can even trim the motor fully down so water will run down back of motor not into carbs and remove the thermostat housing and idle the motor breifly to assess how much water is pumped at idle.<br />PS I have the same motor and I'd love to buy your motor if you junk it but when you fix this problem I'm sure you start to appreciate they are basically good motors. If you dont have gearcase problems almost nothing else goes wrong Mine has run in salt water for 18 years and gearcase is the only cause of concern<br />I'd bet heavily on a water pump problem.<br />regards <br />Sirles pat

 

[fish4970]

Re: 85hp suzuki still overheating

PROBABLY COST PROHIBITAVE TO SHIP<br />TO AUSTRALIA

 

[jim dozier]

Re: 85hp suzuki still overheating

While pondering fish's and my dilema (same) for the upteeth time this weekend I was watching the motor as I flushed it and I did notice and wonder about water coming out of the drain holes in the lower unit. I do no know if it has always done that but I began to wonder if my water tube grommet (bottom one) is part of the problem. The last time I had it off it was starting to look a little past its prime. I had more or less disregarded it because the tell tale has good pressure all the time. Maybe it just isn't flowing at the max rate for WOT. I checked the engine in a garbage can and couldn't see any difference in flow with the plate beneath the water pump exposed or submerged. <br /><br />If I go to replace the water tube, how is it attached at the upper end, glue, or just shoved in a recepticle?<br /><br />Also when replacing the impeller in the water pump housing I notice that there is no separate seal at the top of the water pump housing on the driveshaft. How does the impeller seal the hole at the top where the drive shaft goes through. I don't see a separate seal in the parts drawing nor does it come in the kit.

 

[fish4970]

Re: 85hp suzuki still overheating

Jim it has a gromet at the top as well<br />it just shoves in<br />the gromit is formed with a lip so that it fits <br />only one way

 

[jim dozier]

Re: 85hp suzuki still overheating

Fish when you did your waterpump was there any kind of seal at the top of the water pump housing around the driveshaft, or does the impeller itself act as a seal?

 

[fish4970]

Re: 85hp suzuki still overheating

no seal there<br />i was wondering about that myself<br />the clymer i bought does not show one either<br />i really wish i bought a factory book instead<br />the clymer stinks

 

[fish4970]

Re: 85hp suzuki still overheating

i just ran it on muffs<br />with the thermostat & cover removed<br />i have water flowing from head <br />but quite a bit of exhaust coming from the small hole where the t-stat discharges into<br />it seems like the exhaust pressure is just about <br />enough to equal the water pressure <br />there by restricting flow<br />that would explain why it still ran hot yesterday<br />without the t-stat?<br />the only thing else in that passage is the water pressure relief valve<br />where else could the exhaust be coming from<br /> <br />could there be a problem with the powerhead <br />baseplate gasket

 

[sirlespat]

Re: 85hp suzuki still overheating

I can email you a pdf parts maual if you give me an address.<br />It shows no seal at driveshaft/top of pump.<br />The rubber grommet for the water tube is cheap!<br /><br />I dont remember exhaust gas comming out near the thermostat housing when I tested my motor with the housing removed. I guess that hole leads to the discharge port at the lower rear of the of the power head which normally spits exhaust and water so it may be normal. Or...Maybe there is backpressure in the exhaust for some reason.If you are getting an exhaust bubble in your cooling system wouldn't it sit at the top of the powerhead and cause the upper cylinder head to be hotter than the the lower. <br />In anycase I would expect the PRESSURE to be the measurable. I am still concerned by the 0# water pressure reading at idle in the lake. If the pump is working properly the only cause I can think of for no pressure would be if the exhaust gas goes down the water tube and displaces the water in the pump. This would be more likely if there was a blockage in the exhaust as the exhaust and pump are at similar depths underwater. Mud or sand could be blocking the exhaust path around the propshaft housing. You could check by looking through the hub of the prop with a torch. A really long shot but if the pump is working why no pressure unless on muffs? Perhaps try the removed housing trick on the lake (or test tank)<br />A bit of a ramble on but I am thinking aloud.<br />You must be close! What else is left?<br /><br />Best regards<br />sirlespat

 

[fish4970]

Re: 85hp suzuki still overheating

sirlespat<br />here is my email<br />fishertodd1@msn.com<br />there is not a water flow diagram in the clymer <br />I should have bought a factory manual<br />your help is appriciated<br />and thanks to all who have posted

 

[fish4970]

Re: 85hp suzuki still overheating

jim have you tried this

 

[jim dozier]

Re: 85hp suzuki still overheating

If you are referring to running the engine on muffs with the thermostat cover off, no I haven't. That hole that leaves the thermo housing connects to a channel that runs down the port side of the cylinder head where I believe it exits the powerhead. That portside cooling channel was originally clogged with deposits in my engine and the newer head gasket with the modified channel openings I installed is supposed to prevent it from happening again. I do know that my engine has no exhaust clogs because I have had the exhaust cover off, the powerhead off, the engine holder base off, the exhaust tube off, and the lower unit off and there are no exhaust obstructions.

 

[vidar]

Re: 85hp suzuki still overheating

the impeller itself seals the hoousing...and if you have exhaust at the t-stat you can have a blown ex-cover gasket..that is a great way to get overheat! but if you have the hole for the t-stat open you get no flow furter in the system and the exhaust will blow up there..

 

[fish4970]

Re: 85hp suzuki still overheating

JIM i talked to a suzuki mechanic today<br />he said the comon trouble found with the ghost<br />overheat problem on the 87dt85 is the impeller <br />housing <br />if there is a small grove on the inside top of the housing , it will suck air from the top<br />where the shaft enters and cause the impeller to cavitate<br />he said that he has heard many stories from<br />owners of moters about how much they have done<br />to fix the problem and give up and bring it <br />to the shop and this is what he found to be the <br />problem<br />i will pull mine again tonight to double check<br />and post what i find

 

[fish4970]

Re: 85hp suzuki still overheating

water pump housing looked ok

 

[jim dozier]

Re: 85hp suzuki still overheating

Interesting. I have ordered a new water tube and pump kit and when they come in I will have a close look at it. Early on when I was trying to fix the problem I didn't think much about the housing because the Suzuki mechanic said the housing was stainless steel and should last the life of the motor. I noticed that it was nice and shiny inside with no pitting like you sometimes see in aluminum housings, however there were some grooves I think and I will check them out. At this stage it has to be something relatively basic that I have overlooked (water tube, pump housing, etc.) and I am trying to cover them now. One good thing, since I have retarded the ignition timing 3 degrees,the engine has not overheated once. I dragged 6 people around and a tuber all day at WOT (really hard to get on a plane) and it never overheated, so as a stop gap measure it has worked, but I would like to get the timing back to where it is supposed to be someday.

 

[mrn714]

Re: 85hp suzuki still overheating

Hey just bought DT 85, 1984, How the hell do you get the lower end off to install an impeller?

 

[sirlespat]

Re: 85hp suzuki still overheating

Thom,<br />Undo the gearshift linkage 10mm spanner stbd side under power head (access blocked by rubber bung) and push clear undo visible bolts around gearcase and then there is one bolt near trim tab going up easy to miss! Best is get a manual because there is more to it.<br />Please start a new thread for new questions<br />it makes it less confusing.<br /><br />Fish4970 how are you going?

 

[dgouge68]

Re: 85hp suzuki still overheating

MRN74 check this out

http://store.brownspoint.com/pdf/DT85(83-85).pdf

Also, I have the same overheating problems, I took a break for a few months, I am almost ready to deal w/ it again.. I found Mud Dobbers in the Tstat housing, Hope that was it, Replaced the Water Pump impeller, The old one looked good still. However, I managed to break off a bolt in the TStat cover.Whoever did it last time didn't anti-seize them looks like....Break time..Break is over now.. Also, I suggest getting the SUZUKI manual from the above link..it is better than the Clymer, I have both

Here it is again
http://www.brownspoint.com/

Best of Luck!