1993 Johnson 115hp VJ115tlets warning alarm

[acbill]

Hi, Thanks for reading. I have a 1993 Johnson 115hp VJ115TLETS outboard on a 17' Cobia and the motor's warning horn keeps sounding. I recently disconnected the VRO oiler's electrical plug connections and cut and plugged the oil lines. The motor was getting way too much oil and fouling the plugs. I now mix gas/oil 50:1 and the plugs don't foul. I can run all day at 1,500 rpm with no alarm but when I go over that the alarm starts sounding. I can then back off to 1,500 again and in 30 seconds the alarm goes off. I replaced the water pump, thermostats, key switch, alarm horn and re-torqued the heads but still the same results. The motor runs perfect except for some sludge that comes out of the prop and midsection after a day on the water. I thought the excessive oil from the VRO was causing this sludge to develop. If there is an exhaust leak somewhere will that cause the alarm to sound and then stop when I slow the RPM's? Compression is excellent, motor not overheating. Any comments are appreciated. Great condition motor 9 of 10 and I would like to save it. Thanks!

 

[racerone]

If it is a steady alarm it is an overheat condition.------What values do you get for " excellent compression "------Have you considered looked at the " water deflectors "-------They guide cooling water around the cylinder water jackets.-----Head must taken off to look at them.

 

[acbill]

Hi, Thanks for your time responding. I get 123-125 on all cylinders. I haven't looked at the water deflectors. Haven't removed the heads. As far as water flow I get a good strong stream out of the pee hole and also good flow out of prop and the side vents when the thermostats open so I just assumed it is not overheating. I can hold my hand on the heads which are warm but not very hot to the touch. Overheating was my first suspicion also since the alarm stops when I back off the throttle. The manual said to re-torque the heads but no result from that. This motor was used in JAX, FL so almost all saltwater use. Only about 300 hours on the motor since new. It sat up for quite a while.

 

[emdsapmgr]

As racerone stated, a constant horn is an overheat. The two oiling warnings are variants of an intermittent horn. So, just what horn sound is the engine making? Is the wiring to the VRO tank also disconnected? Just because you have a strong telltale does not mean that cooling water is actually circulating throughout the powerhead. When you had the stat housing apart, did you happen to make sure the small hole in the valve body in the water pump housing was open/clear? If it is plugged up, you'll get an overheat. racer also brings up a good point about the water deflectors in the cooling passages by each cylinder. Normal idle temps on that engine are 143-155. Lower when on plane.

 

[acbill]

Hello Admiral, I have been studying up this afternoon on the fine comments racerone gave me. The horn is constant after 1 minute of WOT. It is good advise to remove the heads and resurface them along with replacing the deflectors. I will also take the thermostats back out and check them if the head work doesn't solve it. But first, thermostat removal on this motor is a bear as it's under the bubble. If I were to get a laser temp gun and do a temp check around the heads would those readings likely tell the story? Knowing the actual head temps going in might save me some time and work as in maybe it's only one side. Also I'm thinking that if both heads show hot then maybe only the water pump hole blockage is the problem. I just replaced the thermos recently and I tried to clean everything out real good in the area. The lower unit is the easiest to do so I'll check that first. A boat shop did the water pump but who knows if the hole is open. Could any of this contribute to the exhaust sludge mess? Could an exhaust problem cause the alarm to sound? Disconnecting and removing the VRO tank and 2 connectors and mixing the gas has cut down on the mess but not stopped it. Thanks for helping me, I'm an a/c contractor not a boat mechanic so I can turn a wrench but on boat motors I'm no expert.

 

[acbill]

Admiral, after reading your comments again I may be unclear as to where " the small hole in the valve body in the water pump housing" is. I was thinking lower unit water pump housing but you said t'stat housing so I am not sure I know where it is.

 

[emdsapmgr]

If you look at the exploded factory parts diagram for the "exhaust housing" for that engine, you will see a composite plate sandwiched between the block and the thermostat housing cover. Item #32 valve body. That's the one with either two pinholes, or a single oval hole at the top. (early models had two pinholes, the later ones had the single oval hole. I think yours is the oval hole.) Using a borrowed laser temp gun may save you time, if the temps look normal when running.... Here is my concern with your problem. On your engine, there are two pressure-relief valves in the stat housing. They open once the engine gets up on plane and water is being forced up to the powerhead. When these pressure relief valves open, the powerhead gets flooded with tons of extra cooling water. So, if they are working properly, you should have lots of cooling water for high rpm operation. Something does not add up here. That's when yours overheats. Maybe the problem is internal- involving the water flow around the cylinders...

 

[acbill]

are the pressure relief valves the 2 plugs with the springs hooked to them? If I took the thermos out and ran it without the thermos would that be a problem. I am in Florida and the water stays pretty hot in summer sometimes 85-90* in the winter it doesn't get below 60. I think I need to check the thermostats but the alarm was sounding both before and after I did the thermo change out. you obviously know my motor and what a pain it is to get to the thermos being stuck up under the bubble. I will try the laser temp gun this weekend with the thermos in and see what I get and I'll post the results. again thanks for your help and you also racerone if you are following.

 

[acbill]

Admiral, If i removed the water jacket covers could I see if there was blockage in the head water jackets? if there was salt buildup what is the best way to remove it, maybe a drill bit?

 

[emdsapmgr]

A salt water engine may show signs of debris accumulation in the water passages around the cylinders. That's not all that abnormal. What you are looking for is that the 4 rubber water diverters are properly in place and that there is no blockage accumulating around them. See pic: it shows a new block and two rubber diverters. the left one is normal, and has lots of clearance between the diverter and the block walls. That exact clearance is what you need to see around all 4 diverters. The rightmost diverter is out of place and will be a problem if it were to re-assembled and run.

 

[acbill]

Morning Admiral, I see the one rubber diverter in place but not the one out of place but that's OK I get the idea. I am just going to rebuild/resurface the heads and change out the diverters and be done with it. I can clean it all out when it's open and make sure all the passages are clear. That wouldn't hurt I'm sure. I will still try the laser temp gun this weekend to see what the head temps are.

 

[acbill]

Hi Admiral, Well my temperature test on the motor confirmed exactly what you and racerone had said supported by the pic you sent me. On the left head, looking from the back of the motor, exactly at the location of the diverter in the picture you sent I got a reading of 141* at normal idle using muffs. All over the rest of the left head and all over the right head the temp ranged from 106 to 116* and I checked probably 10-15 places around each head both forward and rear near the block. It looks like the diverter has a problem like you said causing the motor to run hotter right in that area. If the heads temps increase proportionately as you accelerate and reach WOT then it's likely that the temp sensor on the left side is sounding the alarm due to an overheat situation. The temp sensor is very close to the diverter. I made a video of my test and my boat just to show what we were working on but I couldn't figure out how to get it off of my iphone and onto the site. I would have liked for you to see my 32 year old Cobia Odyssey 170 VBR. I completely rebuilt it top to bottom, it has a beautiful blue hull. Looks better than new with nice Todd captains chairs and a fishing deck up front. I will make the repairs as you guys indicated and post the results. I am only planning to do the left head and not the right, is that OK? Thanks again. BB

 

[emdsapmgr]

You are correct to address the single head problem with a solution. Guess I'm a little bit of a pessimist, in that I'd suspect that if one side is abnormal, the other side is (or will be) a problem soon. I'd wind up checking behind both heads...

 

[acbill]

If I did both sides I'd know they were right. Best approach. Ordering my parts now. Am going to get them at boats.net. Anywhere better that you know of? Thanks, BB

 

[acbill]

boatsdotnet

 

[Fed]

Does this motor have a vacuum operated switch to sense for fuel restriction?
It sort of fits, constant tone alarm that stop fairly quickly when the throttle is backed off and also fits the over oiling.

 

[acbill]

Hello Admiral, Took off the heads and what a mess. I don't see how it didn't blow up. All 4 deflectors were smashed shut no water was going thru any of them. The water jacket was so caked with sand and salt that I can't see how any water was moving at all. Heads and cylinder cover plates are at the machine shop now. I wanted to ask you about the bubble on the back. With the condition of the heads could anything behind the bubble be blocked also? My pee hole tube is connected to the bubble, but it is a strong stream. Could a blockage of some sort be causing the exhaust leak? I wanted to ask before I take it off as it looks like a project. Thanks, BB

 

[Fed]

No water flows through the holes in the deflectors.

The deflectors are there to stop the water taking a short cut between the pistons, they force the water to go up one side over the top cylinder then back down the other side.

 

[acbill]

Hello Admiral, The heads were almost completely plugged with sand and salt. All diverters were collapsed and plugged. The water passages around the heads had blockage with sand in spots. With the lack of water flow I'm lucky the head didn't blow up. The heads are at the machine shop now. I wanted to ask if there are any water passages behind the bubble. I think that is the exhaust but my pee hose is connected to the bubble. It looks like a project in itself getting it off so thought I would get your input before removing the bubble. Thanks, BB

 

[acbill]

Fed, I saw a small hole behind the diverter in the block and the diverter tube had a hole in the center so I thought water flowed thru it. Thanks for clarifying that.