1996 ocean runner hot alarm

[hydra23]

engine J175EXEDB spark plugs QL78YC replace old t-stats with OMC 435491 gauge shows 10-12 lbs idle 800/1000 rpm.

If I bring revs up to 4000/4300 pressure goes up to 25/30 and the alarm goes off. (s.l.o.w. activate) pee hole is strong and engine is not hot to the touch no boiling water no hissing sounds.

flush thru pee hole without t-stats and water flows with ease.

Should I test without the t-stats or just go for the pump and impeller?

Next step is to test the sensor.

 

[w2much]

Re: 1996 ocean runner hot alarm

Does your SLOW activate? Or can you keep the engine running , the alarm go off and you can then resume up to higher RPM before the alarm then sounds again. If so you may have a fuel restriction. It is the same alarm.

 

[hydra23]

Re: 1996 ocean runner hot alarm

Thanks for your response, I read that on this model if the check engine light alarm goes off is because a fuel restriction??the alarm im getting is the hot alarm if I shut down the system reset and the engine revs up again, I can go miles at 3000/3500 anything higher the hot alarm goes off.

 

[Chris1956]

Re: 1996 ocean runner hot alarm

Hydra, You should test your wiring by grounding the temperator sensor (key on, engine not running), and see that the hot light comes on. while you are at it, ground the vacuum sensor wire and see that the check engine light comes on. Checking the low oil and no oil sensors are a bit more complicated.

if the grounded temp sensor does indeed light the "Hot" inicatos, as is should, you might remove it and test it in a pot of hot water on the stove. The thermostats open at 143 degrees, so the sensor should ground at 175 or so.

 

[w2much]

Re: 1996 ocean runner hot alarm

But does your engine go into SLOW mode? or can you bring it down to an idle until the alarm stops sounding and the (hot)light goes off? Do you have to turn off the ignition? I am having the same issue and am also trying to chase down the cause.

 

[hydra23]

Re: 1996 ocean runner hot alarm

Gentlemen thank you for all the info, Chris I will test the sensors and report.

w2much, The alarm goes off (constant) at about 3800/4000 rpm and s.l.o.w. is activated, if I try to rev up the engine will only do about 2500 rpms, the system resets if I power her off.

Thank you

 

[w2much]

Re: 1996 ocean runner hot alarm

Hydra, Thanks for clarifying. Different issue than mine. Follow Chris's suggestion. When I started chasing down my problem I put in a new water pump alrm still went of. When I switched the thermostats I noticed a chunk of silicone perhaps from a previous water pump repair has found it way to the thermostat . I removed it with a real small needle nose plier. Hope you find your solution. Let us know, it helps a lot of people to learn from your experience.

 

[hydra23]

Re: 1996 ocean runner hot alarm

Checked both sensor and they checkout OK. Impeller is due for replacement anyway. I will spend the $50.00 for the kit and overhaul the unit, I was thinking about testing without t-stats but that is below standars.

I will post my findings.

 

[seahorse5]

Re: 1996 ocean runner hot alarm

Check to see if the plastic thermostat capsules move freely inside the rubber seal positioned between the cylinder head and the block. They are the pressure relief valves as the water pressure rises, and if they stick in place, the motor will overheat.

 

[hydra23]

Re: 1996 ocean runner hot alarm

Replace the t-stats with OMC, test and got the hot alarm at about 3500/4000rpm the gauge was indicating 25/30 psi/lbs. What is normal operation at 3500/4000 rmp`s 15/20lbs? The shop manual has no mention of it. Is my impeller weak? I have flush thru the pee hole without the t-stats and water movement is very good.

I checked both sensors and they test OK. Im ready to lower the unit and do a pump overhaul.

 

[Chris1956]

Re: 1996 ocean runner hot alarm

Hydra, If your water pressure is really 25/30 PSi, it should be more than adequate. I guess this leads me to think that the water cannot be expelled from the motor, fast enough. When you run it on the muffs, does water escape thru the prop and between the gearcase and the midsection? What is the temperature of this water?

If you remove the thermostats does it run cool? I am just guessing at this point. It sounds like a water restriction, but I do not have a fix for it.

 

[Chris1956]

Re: 1996 ocean runner hot alarm

OK Hydra, I scoured my OMC Service manual to se if I could find an answer. I have a '98 150 Johnny, so I have a vested interest so to speak.

I did not find a clear cut cause of your overheating. It could be waterpump output, but with the high pressure you are seeing, I don't know. The only other choice is clogged water passages in the head, block or exhaust components. Since finding a cooling passage restriction will require disassembling and inspecting the heads and exhaust covers, I think you should try replacing the waterpump impeller and upper housing. The parts are $50-60 or so, and it may work.

If it doesn't work, I think you need to pull the heads and clean out the cooling passages in the head, block and exhaust passages, or maybe the midsection.

 

[hydra23]

Re: 1996 ocean runner hot alarm

Remove the lower unit today, housing on pump looks OK no visible cracks, a few particles of sand and I guess just normal tear and wear, however the impeller was rotating with little resistance inside the pump housing ??

Took my air compressor and spray from the water tube up, felt the air thru the t-stat on both heads did the same from above with same result.

I guess if the new pump does not resolve the issue I would remove the heads for clean up.

thanks for all the info...

 

[w2much]

Re: 1996 ocean runner hot alarm

Hydra my 2cents again. Here is a hoky test that I performed when I thought I had a water restriction in the head. With the lower uniy and water pump still in place. Youcan also do it with the water pump out just plug up the intake tube for the test and remember to unplug it when you replace the LU. I hooked up a hose to the fresh water washout. I then removed both thermostats. I placed two 5 gallon buckets on the ground to catch the water as it shot out the tstat holes. Turn the hose on full blast and see that both buckets fill at the same rate with the water shooting out of the tstat holes. I found a small hunk of silicone moved up the the tstat opening which I removed. I ran the hose again and found that each bucket filled at the same rate. I had found my restriction. Good luck.

 

[hydra23]

Re: 1996 ocean runner hot alarm

Here is my report

Replace the water pump with original equipment, installed new t-stats and fire her up, water stream is about 15-20 long, hope that was my problem I will follow your sugestion and do the water bucket test nothing to loose other than a water restriction.

Thanks

 

[hydra23]

Re: 1996 ocean runner hot alarm

My apologies for neglecting to report.

After all the above was done the boat run A-OK, most likely I had a weak impeller, also as a safeguard I remove both headcover and clean all visible and non-visible water passages.

Thank you all for your inputs...

 

[w2much]

Re: 1996 ocean runner hot alarm

Thought I would add this to an old post. I finnally figured out why my hot/fuel starvation alarm has been going off. On each long range trip I would fill my built in tank. Each morning at the dock my alarm would go off. I would have to squeeze the bulb then it would stop the alarm. The symptoms would repeat til I got out of the harbor a mile or two. Each time the alarm would sound I would squeeze the bulb , the alarm then went off. I had installed a new fuel water seperator, new fuel lines, cleaned the tank, the filter , the pickup. Could not figure it out. Finnally through reading post here and backsteping all of my past procedures I came to realize it was either a sensor or ?????????????. On my last trip while filling the tank as usual fuel spit out the vent when full. This is how I have known the tank was full. While leaving the harbor once again as usual the alarm went off. Kinda pissing me off. Then it came to me. When I installed the new fuel and vent lines I purposely left an S in the vent line. My thought was that while washing the boat and motor at the end of the day water could not enter the tank as I had put an S in the line to catch the water before entering the tank it would stay in the S instead. Well it turns out that the S held enough water or fuel after fill up to prevent the tank from venting. I leaned over the edge of the boat while my fishing partner held my ankles to keep me aboard and blew into the vent. Sho nuff it bubbled, I blew out the fuel or water trapped. In short my tank was not venting, the vent line was filled with fuel. Sometimes it is the simplest of remedies. Hope this helps someone.

 

[Chris1956]

Re: 1996 ocean runner hot alarm

Way, You are suppposed to tie the vent hose up highest between the tank and the vent, not have a belly in it, as you found out..