Johnson Evinrude 115 Overheating

[modernrocketry]

I have a 1996 Johnson Evinrude 115 Powerhead mounted on a TurboJet jet drive. Although it appears to be in inboard, the engine is a typical J/E 115

The engine is overheating after running for a short period -- even at idle.
There is no water pump on this engine, the jet drive diverts part of the output back into the engine for cooling. while out on this trip, the sea strainer bowl cracked and started leaking badly -- so I bypassed it for the short term until I could get home and replace it.
I have been running the boat in some very sand conditions and beached it at one point (accidentally)
I believe the cause of my problem is sand/debris clogging the cooling lines.
To get at the thermostats on this engine, I have to lift the powerhead out of the boat --(FUN!)
So I was curious if anyone thinks flushing it might clear it up?

To flush the engine, I have an adapter that connects to a garden hose and mounts into a port on the jet drive. I then start the engine and turn the water on. I keep the water pressure down for fear of flooding a cylinder.

FYI, I'm sitting on the backside of Catalina for 2 weeks and got LOTS of time to kill... Thanks in advance for your help.

 

[ezeke]

Re: Johnson Evinrude 115 Overheating

Flushing may help, but the problem is the sand particles that should be stopped by the sand filter will block the small bleed holes in the thermostat valve body so that the thermostats don't know when to open.

The pressure relief valve in the jet drive is supposed to maintain water pressure at 20 PSI, but if debris gets in the valve (it's just a spring loaded nylon ball) it will stick open and cause reduced water pressure.

The waterflow between the impeller housing and the transom plate is only sealed by an o-ring, so if the drive is not adjusted tightly against the transom plate you can easily loose water pressure there as well.

 

[modernrocketry]

Re: Johnson Evinrude 115 Overheating

I checked the drive against the housing and it is very tight -- and the water temperature of the Pacific was cold!!!

I contacted the only boat repair shop on this side of the island and arranged to be pulled outta the water tomorrow -- to try and flush.

Since I have plenty of time, I thought I would pull as many hoses as possible and see what I could find inside. Inside the hose that runs from the jet drive to the bottom of the engine (the one I bypassed the strainer) I found a small piece of plastic about 2X the size of my thumbnail. I continued and found no trace of debris in any other hoses.

I pulled the hoses off the top of the engine that come together in a "Y" and go into the muffler -- there was excellent water flow when the engine was cold. However I don't think this tells me anything.

I decided to run it and see if that plastic was my problem. I used an IR thermometer to scan the temp of the engine heads while running. Both sides stayed between 130 and 148 depending on the RPM, although one side was consistently about 7 degrees hotter than the other.
The engine never overheated.

So tomorrow morning when the ocean is calm, I'll take it out with my son trailing behind in the small dinghy (for a tow back if needed) and put it through its paces.

Does anyone know what temperature the overheat alarm sounds? I'd like to know how far from it I am running.

 

[ezeke]

Re: Johnson Evinrude 115 Overheating

203? f. +/-6?; the switch reopens at 170? f. +/-.

 

[modernrocketry]

Re: Johnson Evinrude 115 Overheating

What do you think about the temperature of the heads as I ran it?
The temperature of the water here is 68 degrees today.

 

[ezeke]

Re: Johnson Evinrude 115 Overheating

Sounds good.

 

[bob johnson]

Re: Johnson Evinrude 115 Overheating

203? f. +/-6?; the switch reopens at 170? f. +/-.

this is in my 1995 115hp 60V V4 manual for the temp switch check:

I thought I saw a jet boat one day with a 60 degree looper 115 in it just like mine...

other wise if the OP has a non 60 degree looper V4 ignore this post!!!

I jumped in because I did the hot oil test on my sensors and this is what i used to check them of the four i had one was bad!!! well out of spec anyway

bob

 

[ezeke]

Re: Johnson Evinrude 115 Overheating

As he said, it's a 115 TurboJet engine. Different switch, different engine (crossflow), different temperature range. TurboJet crossflow temperature switches have only one wire and that is tan.

 

[bob johnson]

Re: Johnson Evinrude 115 Overheating

As he said, it's a 115 TurboJet engine. Different switch, different engine (crossflow), different temperature range. Temperature switches have only one wire and that is tan.

all temp switches?? or the OP's?

if so, what is the book calling my temp SENSORS?, a switch?

is there a difference?

livin and learning

bob

 

[ezeke]

Re: Johnson Evinrude 115 Overheating

http://cgi.ebay.com/ebaymotors/ws/e...304&_sacat=See-All-Categories&_fvi=1&viewitem=

 

[bob johnson]

Re: Johnson Evinrude 115 Overheating

http://cgi.ebay.com/ebaymotors/ws/e...304&_sacat=See-All-Categories&_fvi=1&viewitem=

neat.....

I swore i looked into the back cover of a jet boat in the last year and saw MY MOTOR!!!

a 60 degree looper, same optical OIS ignition...

do you think it was a custom job???

I was thinking if it has problems i could but it for motor parts!!!


bob

 

[modernrocketry]

Re: Johnson Evinrude 115 Overheating

I took the boat out this morning with my son driving our small dinghy as a support boat if I needed a tow.

I ran it hard and WOT in circles for a while, pulled back the throttle and checked the head temp -- One side was around 158 and the other around 165
The hottest temp I was able to record was 168 after running hard and checking very quickly -- and it dropped to 150's quickly while idling.

No overheating. Today's problem solved!

Thank you very much for you input -- it was key to solving this probelm and restoring my trust in this boat again