1990 SP 587 Overheating

[Raymond 88]

Hi, I am new to the forum. just purchased my 1st sea-doo. Was told it was a newly re-built motor on a 1993 SP but now i know it is a 1990. Interesting how much you learn about your machine after something goes wrong.
The problem I have is this. Machine seems to run fine on land running off a garden hose through the back-flush tee. when I tried it in the lake it overheated in 6-7 minutes. Buzzer went off and it was very hot. DOes appear to be any obstruction in the intake grill. Machine seemed to have good power & speed the few minutes it was running. Hooked the hose back up opn land and seemed to run ok again.
Any ideas would be much appreciated

 

[rvaughn704]

Hi and welcome to the forum.
First all I hope you are running it on the hose for 6+ minutes.
I would check the hoses for any blockage.
Check to make sure the hoses are routed right. You will need a manual for that.

 

[Raymond 88]

Thanks rvaugn704. Trying not to run on the hose for more then 4-5 minutes as that is recommended because drive line seal has no cooling when out of the water. When running on the hose not getting water from the bleed line coming off the top of the tuned pipe. Should I be pinching off the cooling line that exits the machine after the T where I hook up the hose? Could I use compressed air at say 60 psi to clear the lines. I have a shop manual and the lines look to be correct. Thanks

 

[rvaughn704]

Not sure about pinching the Line after the T. I would have to look at my manual and i am not at home to do that right now.
As far as the air I think that would be okay. I use weed eater twine also to clean out the pee holes out the back of mine also.
I diffently think you have a blockage somewhere.
Had this ski been sitting for a while ????

 

[Raymond 88]

Could very well be the machine sat a couple of months. Person I bought it from purchased the machine in March from a somebody that rebuilds Sea Doos. Can see new gaskets all around on the top end. Compression is about 135 on both cylinders cold. Just doesnt make sense that if you put the time and effort in to rebuild the top end that you wouldn't check the flow of the cooling lines. The problem seems to only be when it is in the water and not running off the hose. Next problem is it is at our cottage on the lake and I will not be able to get at it again until sat. I appreciate the help

 

[Coastiejoe]

Max run time on the hose should be 1 minute. It is NOT designed to cool the engine. It is to FLUSH the engine and cooling lines. When on the hose, the water runs in reverse of the normal water flow that the pump/impeller provides. The short run time is two fold. Cooling of the engine and so that the carbon seal does not get destroyed. It is pretty common for sand to block the "IN" side of the head and create a cooling issue. While on the hose, the water can get past this as it passes through the head and then can dump out the exhaust or the weep hole.

So you do get cooling while running on the hose, just not as much as running in the water. Remove the hoses off the heads and blow them out with air. See if you get sand coming out. The most common place is the elbow just before the head on the inlet side I believe.


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[RodInEscondido]

Amplifying on the above ... and assuming you have a genuine 90 SP with stock 580 engine (last 2 digits of hull id specify year) ...

I have found that the thru-hull for the drive shaft gets very hot after 30 seconds so I keep my out-of-water runs to 20-30 seconds and do not even connect the back-flush unless I specifically want to back-flush and, of course remember the critical sequence: engine on, water on, water off, engine off.

The in-water flow is from the jet pump along the left side to a "T" connection; the "T-off" goes to the exhaust; the straight-thru goes to a (do not know the official name is) divider located on the block directly under the exhaust manifold. This divider divides the cooling water flow to the bottom of the cooling jacket of each cylinder, subsequently up the cooling jacket, over the head and out. Inside this divider, which is kinda a PITA to get to, seems to be a collection point for crud.

If the engine was actually rebuilt, I would assume (bad word) the cooling system would be cleaned out and you could easily remove the cooling jacket on top of the head to do a quick check and replace the cover without damaging the seals. If the bolts do not come loose easily, be very careful.

You do not state which part of Canada you reside (big place and I have only been in BC and Yukon), but salt water aggravates everything, especially cooling systems. The overtemp alarm (sensor on top of head) is set to 212 degrees f which is really too high in my opinion. All marine gas engines I have seen with raw-water cooling have 160 degree f thermostats to prevent the cooling water from getting close to boiling.

The little vents such as the pee hole at the rear tend to be prone to having little insects crawl in and clog things.

I imagine blowing in a little air into the hose that goes to the above-mentioned diverter may help, but I would certainly remove/clean inside that diverter plate because if one side is blocked you will still get air flow. I would be very careful regarding pumping in high pressure because you have the outside chance of blowing some of the crud back into the exhaust ports.

Oops, another disertation.

Good luck and have fun,

Rod

 

[Raymond 88]

Thanks, that is exactly the type of info I was looking for and you dont really get from the manual. Really great response to my 1st post. very encouraging for the novice jet skier and soon to be repairer.
We are located in Bayfield Ontario on Lake Huron just across from Michigan.
I cant wait to get up there on sat to check out the suggestions. One other thing. Is there a trick to running these things without a neutral in the water without them wanting to take off on you?
Thanks Again

 

[Coastiejoe]

Everything I own has Forward and Reverse. One fully electronic which has a neutral. The other has a manual lever. On the manual one, I just pivot the lever about to the middle and it acts as a neutral.

 

[IDoSeaDoo]

So does water come out of either of the two pee holes in the back when you're in the water? Are you sure the clamp wasn't left on the cooling hose when you put it in the water? I have a 587 and that damn thing runs hot as hell. that's just how they designed them to run, but the beeper should definitely not come on. I've given up on trying to lower the operating temp on this motor, and noone seems to truly know how hot they're supposed to run anyway. I seet it at upwards of 180F on the upper outside surface of the jug, near the head, with a laser thermometer. It seems run fine though, so as long as I see two streams of cooling water coming out the back, I just ride and always listen for the beeper.

 

[RodInEscondido]

Thanks, that is exactly the type of info I was looking for and you dont really get from the manual. Really great response to my 1st post. very encouraging for the novice jet skier and soon to be repairer.
We are located in Bayfield Ontario on Lake Huron just across from Michigan.
I cant wait to get up there on sat to check out the suggestions. One other thing. Is there a trick to running these things without a neutral in the water without them wanting to take off on you?
Thanks Again

Regarding taking off on you: keep the safety tether connected to your body. ;-) Ignoring this and if your steering is nice and loose, it may go into hard turn and you may be able to catch it on the way past; if you test this, please post results (video would be best). Keep smiling.


IDoSeaDoo
All, or almost all, of the angled fittings to which various cooling lines are attached are specific sizes for specific locations. You may have obstructions that need to be cleared out or someone may have put the wrong orifice size in the wrong place or worse yet, replaced with standard wide-open fittings which would affect flow elsewhere.

 

[IDoSeaDoo]

Believe me, I know I have literally inspected (and verified the number of) every single fitting and orifice in the system. I've even pulled hoses off in the water to make sure water was going through them. I could not find any reason for my hot engine temps, except maybe that the pump itself isn't putting out the correct amount of water. The port pisser does seem a bit weak, and that's the water that comes out of the head (and comes out super hot). I don't know what the deal is and there is no real numerical information out there (like flowrates or temperatures) to do any real testing. Noone could even tell me what their engine surface temps are. I've been chasing this issue for years, I believe I have at least two threads on the subject. All I know is that it cools itself, and 5+ fuel tanks of running like this has not dropped compression figures (rings/pistons aren't being fried), so I'm opting to believe that it's okay. Afterall, 185F isn't THAT hot for an engine. The 4tecs are designed to operate at that temperature by design, as are all vehicles on the road.

 

[Raymond 88]

Thanks I Do Sea Doo. We are pushing past the 200 degree mark to make the overheat buzzer go off. I am with Rodin Esconsido. The set point of 212 on the overheat alarm is to high and probably to late. Since I have hit it once already I will be very careful to try to avoid that again. I think the key may be that the engine does not overheat and water is coming out the head cover bleed hole great when it is connected to a hose. When its in the water I don't think we are getting proper flow that far so I will work my way back from there with the cooling hoses.
Either that or find a real long garden hose that reaches the middle of the lake : ) Just kidding

 

[IDoSeaDoo]

Yea, I know the 90 SP had two spouts in the back. you should be getting two streams when it's in the water. These are self-draining systems, so it may take a few seconds to get the cooling system fully primed with water.

 

[RodInEscondido]

Now wait, isn't this a work day? Whada ya all doing hanging out here? I am laid off/retired so have an excuse.

This looks like a good place to address this issue; I know the cooling stuff has bothered me a bit.

To save the need for a long hose, I see Harbor Freight has a gas-powered water pump on sale ... maybe that and a mini-barge will work.

Here is a picture of the mystery "flow divider" on an engine I acquired just to play with. Note the junk in the ports where you should have cooling flow to the cylinders/heads. Yes, salt water is a serious complication.

I have a couple 89-91 skis not in the water yet that I probably will use all clear stuff just to see flow.

Seems to me, in other marine engine research, that salt water will start to chrystalize significantly below boiling point, thus the 160 thermostat. Automotive and marine engines with heat exchangers/radiators and closed systems work at higher temps.

Go have fun this weekend.

 

[IDoSeaDoo]

Oh wow, yours is a true 90, maybe even 89. I have personally never seen a yellow motor, or salt corrosion that bad on a rotax. Yikes! You may want to tear the head off that and inspect around the jugs, maybe break up some of that nasty corrosion and vac it out. That's got to be at least a big part of your problem.

 

[Raymond 88]

Hey IDoSeaDoo. The pic was actually submitted by Rod in Escondido as an example of what I am probably going to find when I get it torn down that far. Crazy busy right now so only had a couple of hours to work on the seadoo this weekend.
The advise from the forum steered me in exactly the right direction. Thanks again for all the great info. Started by working back from the bleed hole on top of the engine using 60 psi compressed air and intermittently running the engine on the hose for short bursts. Disconnect the cooling hose from the pump and briefly pinched off the hose from the bottom of that tee to the tuned pipe. No flow at all through the cooling jackets/ exhaust manifold ( I believe the pic above is the divider in the exhaust manifold) Tried it in reverse direction ( backflush ) also. Removed the head cylinder cover and inspected. It looked fine. Pinched the cooling water hose between the backflush tee and the exhaust socket briefly. Not a drop of water coming out of the tee where the pumped cooling water is supplied. Looks like almost 100% the blockage is in that divider in the cooling water intake divider/exhaust manifold. My question is this. since I am working on this at the cottage with limited resources/tools what gaskets/o-rings should I have on hand before taking out the tuned pipe? Will i have enough access with the tuned pipe out or should I plan on removing the water divider/exhaust manifold to? Thanks again for the help.

 

[IDoSeaDoo]

On the white motor, there is one fiber gasket where the pipe mates to the ex. manifold, and the ex. mani has two gaskets where it mates to the cylinders. That's it. The head has two O-rings to serve as a head gaskets, and those are usually re-usable. The head cover has a rubber gasket that is also usually reuseable too. It's real easy to pull the head off and inspect the cooling jackets. If it leaks a little after reassembly, your bailers should be able to suck it out as you're riding. If you decide to pull the jugs, you will need a new base gasket (definitely NOT reuseable). The exhaust gaskets aren't reuseable either (exhaust leak will fill up your bilge and choke your motor at high speeds), but most of the rubber gaskets usually are (though it is a good idea to replace them once you take them apart).

 

[RodInEscondido]

Oh wow, yours is a true 90, maybe even 89. I have personally never seen a yellow motor, or salt corrosion that bad on a rotax. Yikes! You may want to tear the head off that and inspect around the jugs, maybe break up some of that nasty corrosion and vac it out. That's got to be at least a big part of your problem.

Sorry to confuse ya; I should have added the note that this was not a production engine. I picked it up for about $20 so I would have something I could play around with and learn a bit without messing up an engine out of one of my skis. This engine was frozen up when I got it; when I was attempting to give an example of removing the pto the beast freed up and the cylinders look amazingly good, but the crank rumbles a bit when it turns over. PTO never came loose, but that is another story. I have not done any cleanup until I get a good set of pictures showing the effects of an engine used in salt water and not flushed after each use.

Good note tho regarding the need to remove the head and check the other side of the cooling jacket; the ones I have pulled the heads off of have had a significant amount of sand and other crud settled in the bottom of the jacket. Of course this means replacing the 3 sealing rings around the base of the head and around the cylinders.

I will wander out and try to take a couple more pictures of inside the cooling jacket with the head off.

Rod

 

[Raymond 88]

Trying to get my stuff together to pull off the tuning pipe and exhaust manifold this weekend. Local dealer just told me that they don't sell the gaskets or o-rings for the 1990 587 rotax anymore and they can't get them.
Anybody know where to get these gaskets in Canada or alternatively the USA. Do you think the exhaust manifold to the tuning pipe gaskets from the newer 587 (post 1992 white engine) would fit the 1990 yellow rotax? Thanks

 

[IDoSeaDoo]

maybe try SBT?

 

[RodInEscondido]

Trying to get my stuff together to pull off the tuning pipe and exhaust manifold this weekend. Local dealer just told me that they don't sell the gaskets or o-rings for the 1990 587 rotax anymore and they can't get them.
Anybody know where to get these gaskets in Canada or alternatively the USA. Do you think the exhaust manifold to the tuning pipe gaskets from the newer 587 (post 1992 white engine) would fit the 1990 yellow rotax? Thanks

The 91 should be the same, would need to check the part numbers to be sure, likewise for the newer models with 587/white.

 

[Raymond 88]

Hi, You are not going to believe this. finally had a chance to tear the SP 580 apart on Tuesday. Tuning pipe off, exhaust manifold off, Cylinder head cover off. could not find any blockage. Got lucky and put it all back together with the old gaskets because having a hard time finding the exhaust gasket set in Canada. Tested the sea-doo in the water. Still only water coming out of the left bleed hole from the exhaust pipe but a strong stream going 4-5 ft. At this point thinking it has to be water jackets blocked internally, the pump is weak or when they guy did the rebuild he mixed up the calibrated fittings for the coolant or just used off the shelve fittings. Disconnected the hose from the jet pump with cooling water supply to the engine. Bumped the engine so-so flow. Started the engine for 8- 10 seconds and appeared to be pretty decent flow through the hose.
Pulled it out of the water and trailered it. Did not have my computer up at the cottage. When I got back to the city late last night I take a look at the picture Rod attached. Got kinda of a sick feeling. Had everything apart and did not take the cover off the side of the engine where the cooling water went in. Da. Up to then I wasn't thinking the cooling water went through the tuned pipe before it goes through the engine.
My quick question is do I have to take the starter off to top remove that plate and hose to access the diverter?

 

[RodInEscondido]

When ya go out to play, you are correct in leaving the computer behind.

I just went out and checked one of the assembled 90 SPs I have in the fleet and it appears that you can get to the bolts to the divider cover plate without removing the starter, but it is tight and you would need mirrors to see anything.

Attached is view inside with head removed. The input from the divider is open under the exhaust port so flow is up both sides of the cylinders and up into the head cover.

I think it is time to remove the head and have a look. Do not reuse the o-rings (around the cylinders anyway). Be very careful removing the head bolts (I have been intermittently trying to remove a couple bolts broken off by previous owner of one 90 SP).

Rod

 

[Raymond 88]

Thanks Rod. I am a little hesitant to remove the head as the guy that sold me the seadoo said he would refund the money if we could not find a cheap/easy fix for the overheating problem He seems straight up and when he bought it this spring it was sold to him as rebuilt last winter. We also can not get the gaskets for the 1990 around here anymore. Can still order the from the states but the shipping is more then the gaskets ie at SBT exhaust gasket set of 3 is $9.95 and shipping is $39.95.
Next questions are these.- tried everything to try to get the 2nd bolt out behind the starter for that plastic diverter pipe on the engine that comes from the tuning pipe. Looks like I do have to get the starter out of the way which I think means I would have to pull the engine. What I did notice when I had everything apart is if I blew in the the rubber hose into that plastic diverter and blocked the end of the diverter that goes to the calibrated drain hole there seemed to be pretty decent flow out of the bleed hole nipple out of top of the cylinder head cover. This is where I do not get any water when I run it in the water. Could it be possible that they have something wrong in that drain hose off of the plastic diverter that goes to a calibrated drain fitting. Does anyone know what size or spec that calibrated drain hole is suppose to be.Thanks