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Author Topic:   Johnson 115: One Cylinder Bank Hotter Than Other
PeteB88 posted 07-24-2012 07:08 PM ET (US)   Profile for PeteB88   Send Email to PeteB88  
After replacing [the] impeller [on the water pump of a Johnson 115-HP outboard engine] and flushing the cooling system with air and garden hose, the Starboard side cylinder head was hotter than the Port side, but no overheat alarm [was sounded or indicated]. I installed an impeller kit, got the lower unit bolted up, linkage linked, and fired up the 115. The tell tale [water stream] was super-strong, and [the manner in which the] motor ran [was] great. However, I continually monitored cylinder head temperature by hand placement, and, within five minutes, the Starboard cylinder bank was noticeably warmer than the Port cylinder bank. After eight to ten minutes I could not hold my hand on Starboard cylinder bank for more than a few seconds, but [on the Port cylinder bank it was] no problem [to hold my hand on the cylinder bank]. I could keep my hand on it as long as I wanted. I let [the Johnson 115-HP outboard engine] run a few minutes longer to see if an over-heat alarm would sound, but no audible over-heat alarm [sounded, un]like before.

I pulled off the lower rear cowling and am working on bolts on thermostat housing. There was some serious looking gunk in the Starboard-side hose connect[or] that looked like red leafy membranes about the size of a quarter.

Suggestions? Ideas? I suppose the logical question is what to do if one side of a four-cylinder Johnson 115 runs obviously hotter than the other.

Standing by.

This is an update to the Jelly FIsh, Mud, Weeds, Sand causing Overheat Alarm thread by Chuck Tribolet and similar problem I encountered and answered on same thread. This is valuable information for other Johnson and Evinrude owners regarding overheat alarm, impeller and thermostat installation.

jimh posted 07-24-2012 07:55 PM ET (US)     Profile for jimh  Send Email to jimh     
The most reasonable explanation why one cylinder bank would be hotter than another is from a difference in the amount of cooling water that is being circulated by the cooling system to each cylinder bank. It is normal that the cylinder bank which is taller--usually the Starboard side cylinder bank--will run slightly warmer than the other cylinder bank.

Your method of measurement of temperature by placing your hand on the cylinder bank is not particularly precise. I recommend you invest in a thermometer to measure temperature. You can typically measure the temperature to a resolution of one degree with a thermometer. I do not know how precise you hand is as a temperature measurement device.

PeteB88 posted 07-24-2012 08:02 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
I agree and thanks Jim but barnyard method is all I have tonight. I can affirm I can hold my hand on one side (port) and can keep my hand on starboard side for just a few seconds so differential is dramatic thus significant. Maybe I should have tried a meat thermometer. In fact, Dave from Lockeman's suggested the touch method a couple weeks ago when I started on this project. In fact he suggested a count method - like how many seconds can you hang on to it? .

I am convinced there is a blockage and will start with thermostats per other recommendations on Chuck's thread. The motor is in such great shape I don't want to ruin it.

Mr T posted 07-25-2012 09:49 AM ET (US)     Profile for Mr T  Send Email to Mr T     
I would go with thermostats as you have suggested, but you may need to consider pulling the heads and checking the deflectors. These are pieces of 3/8 ID fuel line that are used in the water passages to route flow around the cylinders. I have been chasing an almost identical situation on my 1990 Evinrde 88 SPL outboard motor and in the process found them to be misshapened and compressed. This is after doing the water pump, thermostats head and head cover gaskets.
Mr T posted 07-25-2012 09:52 AM ET (US)     Profile for Mr T  Send Email to Mr T     
A bit of hisdtory on the deflectors in these motors.

The water deflectors are actually 3/8" rubber tubing (fuel line), so they should be almost perfectly round. There are slightly raised portions of the aluminum casting that surround the cylinder sleeves that keep the deflectors from moving out of line.

(Water Deflectors)
(J. Reeves)

Water deflectors are actually lengths of 3/8" outside diameter rubber hose, installed between the top cylinder and any cylinder beneath it, and also between the bottom cylinder and the block. The purpose of the deflectors is to have the water follow a definite path around the cylinder walls. Unfortunately the deflectors between the cylinders will at times swell sideways due to either a previous bad overheating problem, or simply due to age and salt corrosion. This causes a water flow restriction which usually allows the water to cool sufficently at low rpms but not at the higher rpms.

This hose material can be purchased reasonably at any automotive parts type store if you care to make your own, or you can purchase individual deflectors at any Evinrude/Johnson dealership at a somewhat higher cost.

Removing and installing them can be a hassle at times, but not always. I use a sharply pointed scribe with about 1/4" of the tip bent at a right angle whereas I can reach in, jab the tip sideways into the rubber, then yank it out. It's necessary to clean the seating surfaces where the ruber contacts the block with a small rat tail file to eliminate salt deposits etc. When installing the new rubber deflector, coat the deflector and the metal surfaces with WD40 which will act as lubrication to allow it to go in as easily as possible.

Make sure that you insert something into that deflector area before cutting and installing the deflectors if you make your own so that you will be certain that they are the right length and also that they will be seated properly. Usually a very small amount will be left extending about the block sealing area..... simply cut the excess off with a single edge razor blade.

pcrussell50 posted 07-25-2012 08:33 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
My factory service manual for that engine says to test cylinder head temperature with thermomelt candles--if the hard one melts, that head is too hot. If the soft one doesn't melt, that head is too cold. And they're cheap, too.


PeteB88 posted 07-26-2012 09:00 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Thanks and I appreciate your help. I am back to the project later today. Dave from Lockeman's suggested doing a compression check on hot side which I will do today. My gut is to do that and pull the heads off and check absolutely everything, replace the thermostats and the water deflectors. Not seeing them yet I wonder why they didn't make them out of metal?

Replacing the thermostats is going to be a challenge. The housing is at the bottom of the block, back end of the motor, with lower cowling obstructing wrenching. I pulled a plastic shroud off exposing the bolts a little better and can access the two outer bolts pretty well but the middle one is almost impossible. I read somewhere where an owner drilled a hole into the case to access the middle bolt and plugged it with something like a rubber plug ..

I'm going to do the compression test sometime today - I guess the next question is how difficult to remove heads assuming clean up, new gaskets and probably the water flow deflectors. I also checked my Snap On click type torque wrench and it does not dial down enough to torque those head bolts and I do not want to use a junk torque wrench. Time to get the book but any more help would be appreciated.

Thanks again.

Jeff posted 07-26-2012 09:18 AM ET (US)     Profile for Jeff  Send Email to Jeff     
Recently I met a fellow who is a huge classic Whaler Collector in Northeast Mi. He invited me to come and have a look at his storage yard and pole barn full of Whalers. Interested, I drove up and spent the afternoon looking around.

The interesting thing was, on his 18 Outrage that he uses as his main Whaler he had a very interesting Cylinder Temperature Monitoring System. It was a rather simple electronic monitoring system that used easily installed bolt on thermal-couples to head cylinder. He also had installed a simple read out to give either individual cylinder temps or all the cylinders at once. It was a very nice set up.

I recently saw he is starting to produce this and sell them. It seems his business is in it's infancy but he said he is planning to start developing a mass market product. None the less he is selling kits now using his current design.

It may be worth while Pete to install one of these systems if you can really concerned with Block Temps.

Mr T posted 07-26-2012 09:26 AM ET (US)     Profile for Mr T  Send Email to Mr T     
There is no easy way to access any of the three bolts holding the thermostat cover. What I found worked best was to go to sears and buy a 12 point and a 6 point 7/16 inch box end wrench, and grind them very thin with a bench grinder, get access. It is a pain.
PeteB88 posted 07-26-2012 11:35 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Thanks Jeff, super interesting and makes sense - just like piston airplanes with aircooled engines. Looks like simple install too. I would consider installing the rig on my engine but must admit got new ETEC or perhaps something else in mind.
pcrussell50 posted 07-26-2012 04:03 PM ET (US)     Profile for pcrussell50  Send Email to pcrussell50     
Pete, you have one of if not THE best outboards ever made. In fact, even the v4 E-TECs (that we both drool over), inherited it's basic DNA from that motor. In the spirit of the politically charged Walmart thread, your motor was both USA designed, AND USA made, in an era before planned obsolescence. Even if you have to pay a pro to hoist off the power head and do the 'stats, your still miles and miles (and MILES), ahead financially if you fix what you've got. And if course, you can always rent a hoist for $25 and do it yourself and save big $$$. Plus on older motors that can run forever, it's not a bad idea to loosen the powehead bolts every so often and redo them again with some corrosion resistant lube.


PeteB88 posted 07-26-2012 09:09 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Thanks Peter I really appreciate your comments and perspective - I am getting to know that motor very well now which is good. I had no idea the reputation of these motors until I started digging into this problem. That said, something seems to be clogged, the thermostats need to be changed and the housing bolts are tough to get to. I have gotten great advice on troubleshooting from members on Continuous Wave. I also love to do preventive maintenance and as much as I can by myself so a manual is definitely on the list.

So tomorrow I get a flex socket and grind down a box wrench and see what we come up with.

Standing by - will give report as things unfold.

Chuck Tribolet posted 07-31-2012 01:32 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Pete: how goes it?


PeteB88 posted 07-31-2012 10:22 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Well, uh.... ummm... yesterday, right in the middle of assembly with the gaskets gunked up, thermostats, poppets, o-rings etc ready to go, family members from Texas rolled in with their three dogs. Number one nephew and new wife who we had not seen in a long time and never met the wife. It was almost 4 PM and they wanted to go to the beach. So I went into overdrive to try and slam it all together and I lost control of one of the poppets which got loose and rolled under the block. Next, someone handed me a beer and the dogs started rasslin' and so ---- the person I live with called priority and we went to the beach. I had to leave the parts and gunked up gaskets ready to go wedged on the back of the block.

After dinner last night I went back out with an array of lights and enthusiasm (love working the night shift) about 11 PM and tried but big thunderstorm blew in over the big lake and shut thigns down. We just got the cover on the boat, tools in the garage and top on the motor then Kaboom.

Had to Work today, meetings, project delayed and I hope to get to in in the morning.

Thanks for asking - I will file report.

One thing - that official Evinrude/OMC Sealant is terrific.

PeteB88 posted 08-02-2012 12:18 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Wrap Up - She's bolted back together. Initial tests on muffs = Pass.

For you hard cores this is probably funny. I've wrenched on lots of stuff, bikes, cars, dialysis machines and the actual assembly is simple to put together but access sucks unless lower cover removed and there was no clear method there.

Here's what went down sharing a few details for those of you who might do this sometime.

Tool list -
- real long needle nose pliers (saved the day)
- 1/4 drive 6 pt socket and flex extension
- 3/8 drive 6 pt flex socket (sourced at NAPA)
- one paint stir stick
- one 1x2" board ~ one foot long, ( should have cut a wedge on the end - would have worked better
- Official Evinrude OMC gasket goo - non hardening, stays sticky. Worth it.

1) There is no question manipulating all components into a subassembly around and under the "bubble back" casting, lining up two thermostats, two poppet valves, two gaskets, three bolt holes all while compressing two poppet springs requires either some weird tool or four hands and two sets of eyes. To that end, while solo I tried tie wrapping things together and wooden wedges per suggestions from the crew out there. Thanks!

2) So, still solo, I practiced dry fitting the assembly a half dozen or more times until I determined best line, left to right, to insert, tip, twist and slide the parts into place.

3) After the first beer, my neighbor (now everyone needs a neighbor like Gary), a retired tool and die man, rolls in to talk Pesto making with Ellen. He moseyed on over and said "you havent' got that thing put together yet?". At which point he said "if this was my boat I'd get my die grinder out and run a simple hole in the center to access that bolt and modify that lower cover so you can get a freakin' wrench in there..." and I said "lets do that right now." and he said - "let's give it a try first, your compressor probably doesn't have enough air to run the die grinder." I said - "okay"

4) I show him what I rehearsed and positioned the bolts, gunked up gaskets and all the parts and were ready to give it a try. I put a chair next to the motor for one of us to have good access and view from below and the other from the top.

5) I had a wooden paint stirrer and a 1X2" board about a foot long to wedge the parts in place once springs were compressed as we inserted the bolts. Thanks Larry - but it would have been even better if we cut a wedge into it per tool maker.

6) So we positioned the springs into the block and used the paint stick inserted from right side to compress and hold the springs in place. We had to use a big screw driver (real big - or socket extension would work) to put pressure on the middle of the stick.

7) We used some Phil Wood bike grease (any grease would work) to make the plastic poppets sticky enough to stay in place and the thermostats seemed fine probably because of some of the gasket compound.

8) Garry held the springs down while I inserted the assembly from the left hand side. This was tricky but going slow it worked fine removing the paint stick a few centimeters at a time. to the right.

9) Once in place (magic) Garry took the 1/2 and wedged the cover in place so we could insert the bolts.

10) using the modified 7/16" wrench (ground down for easier access - I did that with Larry's advice) I slowly turned the RHS bolt by hex head until it was close to the cover.

11) While attempting the same on LHS, Gary grabbed the extremely long needle nose pliers and began turning the RHS bolt a little more by the shaft instead of the hex - that was genius. He did the same on the LHS bolt and a hell of a lot faster than millimeters by the box or open end wrench.

12) once the side bolts were clearly in place (being careful not to tighten at all) I inserted the center bolt and with flex socket, got it in place

13) I went through tightening sequence and after looking around for any parts we forgot to put in - we were done!

14) TRIAL - I hooked up the muffs and fired up the motor, inspected for leaks (had to tighten one clamp) and let her run. Tell Tale was strong ( yep, like pissing over a six foot fence).

As the motor warmed up I used the digital thermometer (just picked up from Harbor Freight for about $38 bucks) and took readings. After about 10 minutes or more the RHS was running around 128-130 F and the LHS was around 122 - 124 F. I let it run probably 15-20 minutes and the readings were about the same.

15) today - heading to the lake a little later .

Thanks so much for all your help. And yes - I'm gonna let Gary loose with his die grinder to modify that bottom cowl. Why not?? There is no structural risk and it makes sense.

PeteB88 posted 08-02-2012 08:32 PM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Ran NE end of Spring Lake to Lake Michigan and back - nice and messy chop maybe 3s out there, fun as hell and motor worked flawlessly.

Coast Guard Festival in full throttle in Grand Haven - and blue berries are about over here from what I've been told so get to the beach!!

Thanks and have a blast.

brisboats posted 08-02-2012 09:38 PM ET (US)     Profile for brisboats  Send Email to brisboats     
Great ! Yanno the more you rub your hands over it and the more familar you become with it the more likely you are to keep it! Wisemen have said the crossflows OMC v-4's will still be running around with the coackroaches after a nuclear Winter.


Chuck Tribolet posted 08-02-2012 10:41 PM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
Small world. Phil Wood's Granddaughter Amy lives two doors
over from our beach house. She definitely got her granddad's
mechanical genes, and has good taste. She bought it on a
foreclosure and has done a very nice job of fixing it up.

I think there's got to be a way to at least partially remove
the lower cowling. I thought it was impossible on mine
until I noticed that the parts book said there were FOUR
bolts and found #4 under a bunch of grease. After than I
sort remove each side. They both had cables running through
holes but I could get starboard half forward of the engine
and the port half at least part of the way out of the way.

Check the online Evinrude parts site. They have a nice parts
book, but you have to click the + a bunch of times to make
the picture reasonable big. Then if you click the number
on the picture, it will scroll the text to that part.


Mr T posted 08-03-2012 11:11 AM ET (US)     Profile for Mr T  Send Email to Mr T     
Sounds to me like you got it Pete- good talking to you over the past few days.

Go have some fun out there with the relatives.

PeteB88 posted 08-03-2012 11:42 AM ET (US)     Profile for PeteB88  Send Email to PeteB88     
Yep - we decided to take today off, Lake Mich is calm and flat this morning, we're heading out off Muskegon Lake for the rest of the day.

Thanks again -

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