110 bubbleback overheat issue

[Jerseymk2]

Good day all long time browser first time poster let me start with a brief background i'm a mercruiser tech tech i.d.#NJ3612 so im fairly well experienced but im having an issue with an 89 110 evinrude it overheats at idle now this is on the hose with adequate water pressure water pressure on my dash gauge is reading 7-9psi at around 850rpm and raises as it should thru the rpm range i have replaced thermostats all factory brp parts and i have done the whole impeller kit and she still is overheating this is actually on a friends boat (favors are always the biggest nightmare) but i wanna get him in for stripers in a timely fashion as i do my striper fishing from this boat aswell lol any input will be greatly appriciated thank you

 

[Daviet]

Re: 110 bubbleback overheat issue

Do plugs show any signs of water, thinking maybe head gaskets leaking. Thinking maybe pressurising cooling system? Does engine run smooth at idle and through power range?

 

[Bifflefan]

Re: 110 bubbleback overheat issue

The only thing that comes to my (small) brain is a partly block passage after the pressure gauge.
But that may be way off. Im really more of a 4 stroke guy. I take my johnny in when its sick..

 

[Jerseymk2]

Re: 110 bubbleback overheat issue

no sign of water on plugs or in cylinders i left out i popped the heads and inspected the water diverters in the water jackets aswell to see if there were any signs of deteriation or melting they all looked good so i did not change em only new head gaskets has anyone had issues with anything inside the exhaust bubble i have worked on 2 dozen or so johson/evinrudes and this is the first bubblback i have encountered what is inside there just baffling? and is the a trick to removing it i took all the bolts out and tried to remove it but it would only move a quarter inch or so and feel like something internally was hanging up the problem is i cant find any literature on em nor do i know whats supposed to be normal thank u again

 

[emdsapmgr]

Re: 110 bubbleback overheat issue

Check the valve body in the thermostat housing. There are pinholes in it to pass warm water to the thermostats to cause them to open. If these get plugged, it can cause an overheat at idle. The early crossflows have two pinholes, the later models only have one. They are small and do tend to easily clog with debris. This is a difficult thing to checkout on a V4 bubbleback, considering the tight working room.

 

[Jerseymk2]

Re: 110 bubbleback overheat issue

Do you mean on the removable housing itself or on the motor side in by where the springs sit cause on the housing itself the small water passage hole in the center is clean and clear i have had the thermostats out twice now there not that bad to do if you remove the elbow indicator that goes to the tell-tale and loosen the lower pan and wedge a prybar lol i'm really wondering whats goin on inside the bubbleback exhaust itself are there baffles that could melt or move like i said i tried to remove it and it would move a quarter inch and was still hung up un something internally i dont know whats normal with this motor lol thank u again for your replys

 

[petryshyn]

Re: 110 bubbleback overheat issue

the bubble back housing is an assmy of 2 parts. You must separate the outer most housing from the inner in order to remove a hidden bolt. It sounds like you are trying to remove both at once....

Are both banks overheating? What are the temperatures? Are you getting a warning horn?

 

[emdsapmgr]

Re: 110 bubbleback overheat issue

The valve body is a pc of some composite plastic sandwiched between the midsection adapter and the outer thermostat housing cover. If that hole is clear that is good. Have you had the head covers off for an inspection?

 

[Jerseymk2]

Re: 110 bubbleback overheat issue

yes i have had the heads off and have inspected the water jackets and the flow diverters and yes i was trying to take it off as one piece on the bubbleback thats where my issue lies there lol and im getting the warning alarm and according to the IR thermometer the right bank is about 175 and the left bank is abou 170 when i get the alarm plus or minus a few degrees but i shouldnt see anything over 163 externally and yes that hole is clear on the thermostat housing i made sure when i did them it is an oddball problem that i just cant seem to figure out.

 

[petryshyn]

Re: 110 bubbleback overheat issue

I just finished a 93 110 that overheated from sucking air in the fuel system. How is the performance? Is your WOT rpm OK? Is it possible its running lean? Has anyone played with the timing?

Maybe you are chasing a performance problem in the cooling system.....

 

[emdsapmgr]

Re: 110 bubbleback overheat issue

I read from your comment that you had the heads off, but am not sure you specifically stated that you had the head covers off the heads. Maybe I misread your comment. Check for debris inside the head passages by removing the head covers... You can also test for water flow by idling the engine they remove both of the head hoses going from each head to the thermostat housing. You have not mentioned whether you have a new water pump impeller installed. Your engine will turn on the overheat horn at 212 and the horn willl silence when the head temps get back down to 175. 175 is still too hot, as the engine should run between 140 and 155. It can run cooler when on plane.

 

[mikesea]

Re: 110 bubbleback overheat issue

during your inspection of thermos and heads,did you see any signs of sand and or salt/corrosion,if so,you may have debris in the water jacket areas or inside the exhust cover areas that you can see after you remove the outer then inner plates

 

[Jerseymk2]

Re: 110 bubbleback overheat issue

Yes i had the covers off i may have done a poor job of explaining lol and yes there is a brand new impeller / kit in it and no signs of sand or corrosion and i havent put a timing light on it the problem with this motor is the interior is out of the boat so its on a trailer so i cant run WOT but now im intrigued about the lean issue you mentioned my buddy had hired a guy to work on this and the guy turned out to know nothing and started messing around with all the adjustments which i just made a call to find that out as i was writing this so i guess a sync and link is gonna be next but thats what caused the overheat on the 93 huh a lean condition?

 

[petryshyn]

Re: 110 bubbleback overheat issue

The lean condition in my case was a poor quality fuel connector on the end of the primer ball hose. It was sucking air when flexed. You may have other conditions.....leaking fuel lines at connections, plugged jets, weak fuel pump, partially plug fuel filter, plug screen in tank, the list goes on and on.

If a guy was hired to work on this engine, it may have had performance issues supporting the lean mixture/timing theory.

Find out from your buddy if he was able to get good WOT performance and rpm previously after this guy worked on it.

 

[mikesea]

Re: 110 bubbleback overheat issue

on top of the intake there is a timing stop screw with a rubber stopper,did he mess with that screw,that is your timing,i hope he didnt,otherwise you need to time with a timing lite,but,the factory usually places a paint on it so if its turned you my be able to reset,you should understand after looking at what im talking about,

 

[Jerseymk2]

Re: 110 bubbleback overheat issue

yea i have timed and done the sync and link on a few johnsons i used to works at a mercruiser and johnson dealer so i know the motors from having to mess with them from time to time i was there merc guy and they had the outboard guys but i have had to fill in and help them from time to time i re-did the carbs on this motor not long ago and had no problems after that and im running it off of my test tank and line which i know is fine i know all my hose and conections are good as i re-zip tie everything im gonna shoot the timing light on it and hope that its that easy lol but my luck its not gonna be for the life of me i cant get this one figured out so far how but it your experience have you ever seen the overheat sensors go bad and prematurely set the warning horn off ? like i said in a previous post im getting a higher then normal heat reading from my IR thermometer but not to the point where i would completely rule out the sensors being bad at this point?

 

[mikesea]

Re: 110 bubbleback overheat issue

I have seen sensors go bad,but usually either total failure not working ,but I know they can give false alarm.But,you are getting into a heat range via your thermo gun.The only logical thing to me would be a partial blockage somewhere,perhaps in waterjacket,or inside the block,or possibly at the point where the water tube enters under the power head,I have seen impeller vanes break off and get stuck there.What I can tell you is this,here in South Fl.many fishing guides and their mechanics have gutted out the thermostats on the V-4 engines.Debris that does get in there settles in the bottom area where the thermos and poppets are located on those engines.They cut the sides of the thermo at the bottom of the side arms,then cut the stainless round piece on the top,thus letting it fall off the guts.I know ,as a mechanic you want to know the answer,but if your not interested in puling more apart right now,you might want to try it.If you take a long piece of wire,like coat hanger straitened out,pry around up the watertube and shoot water into the cooling system ,maybe?you might find something sturk on top of water tube,Im grasping at straws like you.Hope you find it and let us know

 

[emdsapmgr]

Re: 110 bubbleback overheat issue

Did your friend bring the engine to you because it was overheating? Does it overheat when on plane?

 

[Jerseymk2]

Re: 110 bubbleback overheat issue

i'm definely grasping at straws lol and i already thought about guting the thermostats or do the 1/4 inch washer trick but he runs in 35 degree water and below freezing air temps in january and december up here so i dont wanna mess with operating temps of the motor under those conditions im gonna drop the lower unit again and try a coat hanger in the pick up tube but i dont think its gonna help as i have put the garden hose directly on the water tube and had good water flow u guys are sure there is nothing in that bubbleback baffles or anything that could have moved or melted etc... and yes this motor was overheating and the backup pony needed a tuneup thats why i have this problem on my hands i'm tellin you this stuff only happens when your doing a favor lol

 

[mikesea]

Re: 110 bubbleback overheat issue

there is nothing in there that could melt and blockup anything if thats what you mean,i thought you pulled the bubble and exhust off,but,you are confident there is no trash in there,there are passages in the block that could get corrosion etc ,but usually you would get some idea of that in the other water passages,from what i have reread here,your talking about a 12 degree hot,never more right,point is,anytime i got an overheat situation,it got hot,no messing around,hot,should it get to 175,i guess not,what would happen if u put it back together and brought it on the water an ran the crap out of it,if the only thing you get is 175,r we sure its 175,is you temp gun accurate,at this point you might want to get a temp guage for outboards,see what it says,its just 1 wire,other are at dash,,the only other time ive seen something like this was,barnicles built up inside the water pickup of a sterndrive,but in that case i went to real hot