engine overheat problem need help

[Beejay]

Hey guys,

Just asking if anyone has ever worked on a 89-93 evinrude 120horse V4 VRO outboard?

Ive had an overheating problem with my alarm coming on but the water coming out the back of the motor feels warm.

I took the housing covers off both the thermostats today and the two thermostats look very dicky, did the hot water test and both didnt pass, so went to leisure marine and bought two brand new ones and replaced them.

Dropped boat in at Manly and took her for a test drive thinking I may have fixed the problem with just the thermostats, but 5 minutes out the mouth of Manly boat harbour and the overheat alarm went off again.

Im not a mechanic but im having a crack at it because I know its gonna cost me alot in labour charges, and I have the boat booked in for Monday Morning. Just thought I would have a look myself to save some of my hard earned dollars.

Now that the new thermostats havent fixed the problem, im thinking of unbolting the heads tommorrow and see if theres any kind of blockages in there? I just want some input into wether or not im doing the right thing and if im looking in the right places for the problem.

Ive checked all the spark plugs to make sure there is no water in with them, so im pretty sure I havent cracked the head, I would just like to know what im looking for as far as blockages go when I take both the head cases of tommorrow.

Any input would be greatly appreciated cheers Beejay

[noname]

firstly, are you getting water out of the column,

secondly, check the new thermostats, yes "both" of them, as 1 may be faulty? if you can also check the temp at which they are opening would be nice to know too.

thirdly i would be looking at your impeller if you still have a reasonable water supply comming from the column, where it normally comes through, just below the cowl? i believe. leave the heads to the very last option. as you will pick up on any water entering the combustion chamber.

does the alarm stay on after your on the plane, or it won't let you up to planing speed?

[Beejay]

yeah mate,

There is a steady flow of water coming out of the column, the impellar and housing were replaced with new parts 1 month ago, but I spose a look at that wont hurt.

Took it out from manly boat ramp today, travelled about 10 minutes going slow about 4 knots through the harbour, felt the water temperature coming out of the column while travelling at this speed and it felt quite hot but not hot enough to burn my hand, arrived at mouth of boat harbour and gave it some throttle, travelled about 250 meters at about 25 klms an hour felt the water from the column at this speed and it was quite alot cooler than it was travelling slow on the way out.

Anyway after the 300 meters at 25klms an hour the alarm came on again.

I slowed down and shut the engine down, then got it up on the plane again for about the same distance again but the alarm sounded again.

Headed back in and tried to plane it again but this time it wouldnt get up on the plane and was making noises to let me know it didnt want to.

I decided to go it slow back in again, and it did that okay all the way back to the boat ramp, without the alarm going off.

Do you think I should check the impellar first, even though im sure the whole assembly was replaced in early january?

On the way in today also, I took the engine cover off and felt the heads with my hands to see just how hot they were, one seemed to be hotter than the other, which is whats making me think there is a blockage in the head somewhere and for some reason the water must be Bipassing this section due to a blockage....your thoughts...cheers Beejay

[big al]

i had a problem once outboard would run fine up to about half revs then any thing over the alarm would come on .the problem was the impeller was fine up to half revs but anything over it would not push enough water through to cool the engine enough so alarm would come on .new impeller problem fixed .that is what id look at first al

[noname]

i would be checking the impeller first, i had a similar problem, but it was a thermostat that was failing on mine,i did the test in boiling water and sure enough 1 was just opening, cut the guts out of it and it worked fine, well it kept the alarm off and ran cool i guess, and then with checked new thermostats installed, all is good now. maybe by cutting them or leaving the thermostats out is another way of checking them, but i'm leaning towards the impeller myself. if you do check the impeller yourself, make sure it's in correctly, fins facing the right way!

[Beejay]

Okay so where do I check the impellar???...lol

I am guessing its down somewhere at the point of where you put the muffs on to do an engine flush?

Sorry to ask such stupid questions, but ive never done this before and have only decided to start checking things myself for one to save money and two so I dont get ripped of by boat mechanics that might tell me my head is cooked and my engine needs rebuilding. If all else fails I still have my boat booked in for Monday morning, im just thinking that if I do the heads myself I will save alot of money on labour charges.

I already have to fork out 1300 bucks for extended bimini and storm covers this week as well

Thankyou noname and big al for helping me with this problem...cheers Beejay

[noname]

you have to drop your gear case to get to it, the impeller is more or less what is inside the water pump, and very suseptable to junk, and sand getting into it. it's def not a hard job to do, just tricky to do over the bloody internet, where are you at bj??

[Beejay]

over at chandler mate, mt gravatt - capalaba road

[mick fillet]

another sudgestion if I can say so.

you said the impeller was recently done thats good but a common mistake when replacing the impeller is it a good idea to replace the rubber gromet at the end of the water pump spear (the tube that runs up the leeg from the pump housing).

when putting the lower casing back together you have to align the spline shaft gear shifter and this water pump spear. the spear goes into a ruber gromet and if pinched which has hapened before to a few of my out boards a very similar scenario to what you described occured.the pinched rubber gromet restricts the water flow and sets the over heat alarm off randemly.

I reckon the bloke that did your impeller may have pinched this rubber gromet when putting back together and its whats restricting your flow or a chunk of the pinched rubber has made its way through the little ports some how and is also restricting the flow there as well.

cheers mick

[Beejay]

thanks mick will give that a look as well mate...cheers Beejay

[noname]

going down that way soon with straddie brad, we can pop in if you like and have a look, my number is 0402 450 783 if ya wanna give us a call

[dstrans]

I had the same problem as mickfillet if that is going to help you.

The only thing is i went for pulling the head off first instead of checking the simple things before pulling heads off

[rumrunner]

hi beejay

dont touch the heads mate sounds like you dont have much idea about tourque settings and head prep to be going down that path!

i would recomend not touching the impellor either! something as simple as a stipped bolt or incorrect ipellor placement or having no idea may cause you alot of pain!

my oppinion would be to get the impellor checked or replaced and also get the alarm tested to see if it is faulty?

if that fails then i would do a symple leakdown test to see if your heads hav failed!

after that i would start checking mixtures and tune of the engine!

if you didnt know beejay i do mechanical repairs on all boats,bikes,cars,mowers,engines for $55 phr and im at Tamborine.

go buy a temp gun from repco or autobarn for about $40 and you can point to an area and see what temp it is at!

saves guessing games and sometimes a burnt hand!

cheers Ian

[flexo]

Just a thought but have you concidered that the temp sensor may be faulty???

[Ben Derecki]

Have had similar problems with my Optimax but it's always been the impeller. Good to read the other information though.

Can someone enlighten me on the hot water test though?

[rayke1938]

Ben Derecki wrote:

Have had similar problems with my Optimax but it's always been the impeller. Good to read the other information though.

Can someone enlighten me on the hot water test though?

Drop thermostat in saucepan with a thermoter in it on stove and heat water and keeping it agitated so that temperature is even and observe what temperature thermostat begins to open and also that it opens fully.

I also recommend rumrunner.

Cheers

Ray

[mick fillet]

so beejay how did ya go today did ya get it all sorted or what?

[Beejay]

Okay guys, spent all day on the boat, I dropped the bottom half of the outboard with gear box and water pump, impellar. The impellar and housing was all brand new.

Listened to Mick and noticed that there was no rubber grommet between the impellar pipe and the pipe that goes up in to the engine.

I found the grommet had been pushed down into the top of the impellar housing, I dont think the last mechanic new what he was doing or just didnt bother with the rubber grommet because the connection between the bottom leg and top leg pipes was loose and had no seal to it.

I managed to take the grommet out and re aligned the pipes with the grommet between them to get a better water pressure.

Got it all back together, shit it was hard trying to align the top of the gear selector with the little hinge and screw that holds it in place...lol

I listened to no name as well and took both the new thermostats out again and put them in boiling water to make sure they were working and they were, so put them back in.

I took out both the heat sensors as well and tested them with the ignition turned on and heated them with a ciggarette lighter and after a few seconds they both triggered the alarm of so I figure they arent faulty, the only thing I dont know for sure is what temperature they are going off at?

Took for a test run of Manly again, all seemed good, chugged out and got her up on the plane, got close to king island and the alarm went off again.

Decided to slowly come back in, boat refuses to get up on the plane when its hot.

I really dont know where to go from here, I have it booked in for tommorrow morning, very scary considering ive worked on it all weekend and now im going to give it to expert mechanics after all the labour I did and probably have to pay big dollars.

If anyone has a better idea let me know...cheers Beejay

[Beejay]

Hey rum runner are you a mobile mechanic? Your number would be handy too mate. PM me your number would ya champ? Cheers Beejay

[Beejay]

Whats the idea of the teperature gun? Will that show me if i have a hot spot in the head and if i did would that indicate a blockage in that spot? Cheers Beejay

[Beejay]

I think im going to take rum runners advice though and not touch the heads, I have the boat booked in for tommorrow morning but if rum runner wants the job im happy to cancel the booking.

I live over at chandler in south east Brissy and my number is 0423 047 055 if ya keen...cheers Beejay

Im guessing you would be pretty much booked out like the rest of the boat mechanics though :dry:

[Beejay]

Dropped boat into Wynnum Marine this morning, hopefully all its issues will be sorted by the end of the week and I can do some serious fishing this weekend without stressin about over heating problems.

Im also having some trimming done while the boat is in, getting full storm covers to match the half cabin work, so hopefully all will be good by Friday.

The only thing im worried about is the $$$$$$$ its gonna cost.....

[rumrunner]

sorry for the late reply beejay!

i dont mind who does the job mate as long as its done properly and at a respectable price!

lett us know how ya go mate ? see how far or close we were to an internet diagnosis?

i dont have too much work on at the moment so if anyone else does need work done or if ya need me in the future mate you can get me on

:0409271036 Ian. (cars,boats,bikes & mowers)

Queensland Performance Mechanical

221 williamson rd Tamborine

:55436693

cheers Ian

[Beejay]

Dropped it in this morning, gotta call around 3pm this arvo, they seem to think the engine is running at the right temperature, so they suspect one of the sensors may be faulty and sending an incorrect signal telling the motor its hot when it isnt.

They said they will order the part in the morning and take it from there.

So all I can say is:

Thank God a few of you guys turned me away from pulling the heads apart, because I was heading that way until mick advised me to drop the gearbox first and check impellar.

There was a problem in that area to, so all the advice I got from you guys was very helpful and I thank you all for noticing that I am an amateur mechanic, and knowing that there are things I should not be touching.....lmao

Thanks for the phone number Ian, Its alot handier having a phone number like yours than having to wait two weeks to have your boat looked at, prolly would have been fixed by now had I have known your number 1 month ago.

I know the sensors arent completely faulty cos i took them out myself and heated them with a ciggarette lighter to make sure they triggered the alarms and they both did that.

I guess the problem with them is they are going off when the motor is only warm.

Anyway guys will let you know when I know more later in the week, hopefully I will be out in the bay this weekend touch wood....Cheers Beejay