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Alarm - Johnson 1989 115HP 2T (Help Needed)

B

Byte

Regular Contributor
All,


Just started my outboard (with ear muffs over water pump area) the first time in 18 months - after an extensive storage period of non-usage.


It ran fine up to 3 minutes - then an alarm sounded at the console and i turned it off. I do not know if this alarm was caused by overheating or another tigger…

- the fuel is new.

- water pump/impellor is new (installed just before layoff in 2008).

- new thermostats and confirmed that they do open at the right temps (installed just before layoff in 2008).

- cleaned out cylinder ports and removed all salt grime/buildup after removing heads.

- no cracks / warp in cylinder heads.

- good / even compression from all 4 cylinders.

- fairly healthy water flow from piss hole.

- water does splash out from the propellor area.


- water supply pressure from tap not the strongest IMO.


- both heads were hot to touch.

- all water deflectors in block have been replaced and are not swollen.



Questions....


- best way to test ohms for temp sensors and in what type of oil bath?

- what temp/ohm triggers off the sesnors?

- how to determine if the water supply pressure is sufficient to prevent possible overheating?

- how to determine if this alarm is triggered by a strong vacuum in the fuel line or another cause?

- does a vacuum switch exist on this motor (if so where exactly)?

- where exactly are vacuum switches normally located on other motors?




Advice on next steps to diagnose this problem would be much appreciated......

Byte
 
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In addition to above, the following points are noted......
I have cleaned all cooling passageways, head internals in the block and exhaust area
It is noted that it is best to measure the temp at the cylinder walls, not on the cylinder head because there is very little cooling water around it. The head gets very hot normally and will burn your fingers.
- exactly where at the cylinder walls should running temp. be measured?
- what is a good brand laser temp. measuring device?

I am using OEM oil mixing container which is connected up to motor.
- how to ensure I am not running my 2T fuel mixture too lean (hence too hot) ?
- how to confirm if heat sender is faulty (causing alarm to trigger)?

cameron
 
The heads should not get hotter " normally " than the block.------If it is a steady alarm it is " overheat"---------------possibly not enuff waterflow from the hose !------------Are you running on premix 50:1 untill you confirm that VRO is working !!----------------Test again with boat in the water.
 
thanks for reply.

yes, alarm is constant.

how can i check if the VRO is working properly and without air leaks?

Just as an observation, i note oil film surrounding the a fair %age of the hose length leading to the motor.

how do i ensure i am running 50:1 premix if i am relying on the VRO to deliver the right fuel mixture?

how to determine if this alarm is triggered by a strong vacuum in the fuel line or another cause?


Cameron
 
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Just slow down ------------ test in in the lake !!-------------------------Mixing a small tank at 50:1 may cause a little smoke , but will never damage the motor.----Mark the VRO tank and monitor oil level ! If oil level stays constant VRO is not working.---------------------A constant alarm is " overheat " only.------------------There may NOT be anything wrong other than running on the hose for too long with too little water supplied.
 
thanks for response.

how long is considered too long for tap supply of water through the impellar - before overheating begins?

i still do not understand what you mean/imply when you stated i need to run 50:1 premix until i confirm the VRO is working.....

Are you implying that i need to fill my boat petrol tank up with this pre-mix and not straight gasoline?

So, I will have both the oil from VRO and the pre-mix fuel going into the carbi at same time - until i can confirm that i see movement in oil levels in the VRO tank?

To confirm your statement, the additional oil will not hurt my motor.

What rate of oil usage per hour of operation should i expect to confirm correct operation of the VRO?



Cameron
 
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Just bypass the VRO. Those motors are notorious for blowing up due to a bad VRO pump. They do not give you any warning before its too late. Once its too late, its too late, there is NO saving the motor.

Just cap off the VRO, and use a 6 gallon tank, put 6 gallons of gas and mix it with 50:1 two stroke oil. A VRO that has been sitting for 18 months, in my opinion should not be trusted.

Your alarm sounds like an overheat alarm, and I will bet any amount of money on that. It was probably something as simple as the muffs slipping out of place when the motor was running. Was the motor pissing or was it a slow drip drip drip...
 
Either way---------- mix 50:1 in a portable tank or your main tank untill you confirm oil level going down in the VRO tank.This will NOT damage anything.-----------------I have had motors overheat on a hose before.------------Enuff said.
 
thanks Racerone / johnson140 -

I will try to run the VRO first - along with a smaller independent portable fuel tank with 50:1 premix.

what are the symptoms of a motor being affected by a faulty VRO?
how do u cap off the VRO?

assuming the muffs stay in position on intake, what amount of time is considered too long for tap supply of water through the impellar - before overheating begins?

also - what is the torque (in Nm) for the cylinder head bolts on this motor (A-J110TXCEM)?

My OEM handbook recomends to re-torque these bolts after overheating occurs.


Cameron
 
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240 inch lbs------Should be done once a season.------------------SOME HOSES SIMPLY DO NOT SUPPLY ENUFF COOLING WATER !!---------------------------Most outboards are really well built, but end up on the scrap heap because mistakes were made.
 
thanks racerone.

so, how does one flush with freshwater and not generate overheating conditions?

what are my next steps of diagnosis if after i run motor in the salt and still have the overhating condition?

BTW Johnson140 - the water is 'pissing' out holding a 'good' trajectory.. and not drip drip...


Cameron
 
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When running on a flushette, have the water pressure (hose) turned on full blast. I've run engines in this manner for a good 30 minutes and encountered no problems..... just keep a eye on that flushette as they will move around due to viberation.

The warning horn sounds shortly before the engine is hot enough to do any damage.

Frankly, I'd drop the lower unit to double check the pump assembly and passages. A lot of bugs can find their way into that area in the amount of time you state, and/or the new impeller could very well have taken a set due to being in one position for so long.
 
thanks jreeves.

can u advise what gaskets, etc i need for when pulling the leg

cameron
 
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No gaskets are involved. Normally I replace the entire water pump assembly but that's your judgement call of course.

Best to seal the impeller plate to the lower unit and the impeller housing to the plate with Bombardier 3M Product #847 sealant to eliminate any possible leakage where the pump could draw air.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
 
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