Johnson 115 V4 1977 overheat

promotec · Nov 1, 2004

Hi Guys I have a Johnson 115 V4 1977 115el77 on the back of my 17ft Cruisecraft runabout, while out the other day the alarm buzzer came on and the engine was overheating, I was in the middle of getting unstuck of sandbanks where I had been grounded for a couple of hours. The engine stopped and wouldnt restart (Not seized)I had to be towed back in, the buzzer sensor plastic or rubber surrounds melted in the head cover so it must have been pretty hot, back home I noticed one of the water hoses to the cylinder water jacket had come off. I have done a compression test (while cold) Starboard were 122 top and 122 bottom Port side where about 110-115 top 105 bottom This is pushing the 15 psi varience mentioned in other posts, but still above the recomended 100psi on all 4 cylinders, the motor did start when i tried today after compression test but I turned it straight of due to a hose being still loose, after that it wouldnt restart. Would this show a blown haed gasket or could this be due to a need for a decarb or something like that, I plan to do the impeller and thermostat as the motor was running hot anyway according to the temp gauge, but the day before this happened I had just purchased a $2000.00 new boat trailer so funds to spend on the boat are very restricted for a while so want to get away as cheaply as possible. Any feedback would be greatly appreciated.

dolluper · Nov 2, 2004

Re: Johnson 115 V4 1977 overheat

fix your hose and try to start it again let us know what happens start in the water

ledgefinder · Nov 2, 2004

Re: Johnson 115 V4 1977 overheat

How long was the buzzer on before you stopped? A compression diff in that range is most likely mild scoring. Could also be a stuck ring, or the first sign of a cracked ring or piston land. I'd re-torque the heads & decarb. Best practice would be to pull both heads & take a look. Not much of a job on those V4s. USE NEW HEAD GASKETS (about $20 each at the dealer) when putting it back together, and don't pull the heads if you don't plan on putting new gaskets in. Otherwise, I wouldn't rely too much on the engine (don't go far out in the ocean) until you see how it's doing. That motor's probably not worth rebuilding, so ust retorque, decarb & go might make sense. If it's shot, it's shot - you're not going to rebuild it. On the other hand, the new gaskets will help you see what shape it's in, internally, also the old ones may have been damaged from the heat soak.

promotec · Nov 3, 2004

Re: Johnson 115 V4 1977 overheat

Hi Guys thanks for your advise, the buzzer was only going a few minutes ( I didnt know what it was at that stage) The engine wont start, I wouldnt have thought that the compression as listed above would stop the engine starting, the battery is a bit low from messing around trying to get it started plus compression testing Ill recharge that and see then if it will start, failing that ill do the head gaskets (with new ones)then see what sort of result I get.

Solittle · Nov 3, 2004

Re: Johnson 115 V4 1977 overheat

Those compression readings are not all that bad. Let us know the outcome. I don't agree with ledgefinder if money is an issue in your life. A new 115 is going to run $6,500-7,000 (iBoats). You can get a rebuilt powerhead for under $1,500 and spend less if you do it yourself.

promotec · Nov 9, 2004

Re: Johnson 115 V4 1977 overheat

Well I have played around with the motor as time allows and found that there is no spark, I have taken the advice offered on this forum to diagnose "no spark Probs" eg disconnecting the big red plug, and then trying for spark also have tryed with the kill wire from the power pack disconnected to ensure that this wasnt causing the no spark probs, I have read through hundreds of posts on this forum re no spark probs, it is looking as though it is the powerpack or stator but dont have a multimeter to test ohms etc to further diagnose the problem. Would overheating cause a failure in the powerpack or stator? Thanks guys Ill keep my results posted as I progress, so others may also benefit from my experiences and the answers that are supplied to my thread. Kind Regards Chris

promotec · Nov 12, 2004

Re: Johnson 115 V4 1977 overheat

 I purchased a digital multimeter, recharged the battery, the battery isnt spinning starter very fast with plugs in fine with them outbut will check that out once getting the motor sparking and running. Okay guys heres the results of some testing I have done to ascertain why I have no spark I would welcome some feedback on these results Joe Reeves feedback would ge great as I have followed many of his posts and used much of his advice

No spark at plugs Tested with plugs out, no spark Disconnected big red plug, no spark Disconnected black/yellow kill switch wire from powerpack, no spark tried with and without big red plug connected, no spark either way. Stator Test As listed on forum as follows (posted by Joe Reeves) "The ohm reading between the Brown wire and the Brown/Orange wire should be 630 ohms +/- 75 ohms." Result: brown and brown/yellow wires at powerpack position 7 & 8 tested at 642 ohms resistance "The stator yellow wires.... Ohm meter on high ohms. You should obtain a reading between them but not between either of them and ground. This would indicate the stator is fine." Result: yellow wires at terminal block from the stator y/g & y when red test lead to one, black test lead to the other reading of 0.00 no resistence. This could be the problem yellow/grey tracer wire on position 6 of terminal block, when red test lead to yellow/grey, black test lead to ground = no resistance yellow wire on position 5 of terminal block, when red test lead to yellow black test lead to ground = resistance reads at about 22-30 and bounces around alot. This could be the problem Small Three Wire Rectifier Test as per Joe Reeves tutorial (thanks Joe) Result: all results achieved as per the above resistance tests no probs here Sensor Coil Low Ohms Test Manual says 8.5 + or - 2 sensor leads 2 & 4 on powerpack tested on 200 ohms scale (between both leads) 12.2 ohms sensor leads 9 & 12 on powerpack tested on 200 ohms scale (between both leads) 12.5 ohms Sensor Coil high Ohms Test Manual says infinity, 0 would indicate short to ground meter on high end scale 2000k black test wire to ground red test wire to powerpack lead 2 approx 1650 ohms black test wire to ground red test wire to powerpack lead 4 approx 1650 ohms black test wire to ground red test wire to powerpack lead 9 approx 1650 ohms black test wire to ground red test wire to powerpack lead 12 approx 1650 ohms none of the above testing as zero. Powerpack didnt find a good post that details testing that with a multimeter (digital) It appears that the fault could be with the stator, could this of happened through the motor overheating ? anyone know what a stator is worth here in Australia.? Thanks for all your guys help and advice. Kind regards Chris

Dhadley · Nov 12, 2004

Re: Johnson 115 V4 1977 overheat

Make sure you change head gaskets and deflectors before you get it running. Once it starts it may pump water past the head gaskets (its likely they're blown or damaged). If the deflectors are out of shape and place the motor may overheat again.

dolluper · Nov 12, 2004

Re: Johnson 115 V4 1977 overheat

6amp 247 us 12 amp 257us new price plus shipping

cbelgum · Nov 12, 2004

Re: Johnson 115 V4 1977 overheat

I recall seeing a post that said you should check the stator magnets(?) were properly stuck in place. They do come loose. It may be that you need to take the flywheel off and check, if the engine got very hot it might have affected it. Sorry it is not very precise - perhaps someone else can be more detailed on it.

promotec · Nov 12, 2004

Re: Johnson 115 V4 1977 overheat

Hi Dhadley Yes I will be doing the head gaskets, t-stats, waterpump etc, Im actually waiting on a manual arriving from the USA, it will be a week off yet, Im using a library copy at present but its in their reference section so cant borrow it, just read it there but its still a great help. Hi dolluper Thanks I had seen some USA pricing, Ill have to extablish whether mine is a 6 or 12 amp as parts lists have both listed for the 77 model 115 johnies.Suppose i may be able to see whats in it once pulled down. Hi Seabee61 This is something I can check once getting the flywheel off, I have to locate a three legged puller to borrow to do this. I would be keen on someone commenting on the readings i have posted from the yellow and yellow/gray wires from the stator as going by Joe Reeves posted tests these are giving results that would indicate a prob with the yellow stator wire or whatever its connected to (the stator or an aspect of it) any feedback from you electronic buffs would be greatly appreciated. Thanks guys your feedback is much appreciated and a great assistance in familiarizing myself with this motor etc. Kind regards Chris

badbillr · Nov 12, 2004

Re: Johnson 115 V4 1977 overheat

my '84 140hp evinrude over-heated. you have to replace the over-heat sensors, they are one time use. replace head gaskets as they go bad from heating. had to replace power pack, it is water cooled and sits on top of exhaust, on top of motor. i replaced the t-stats and phenolic plate as well. old stats were frozen shut. your compression doesn't sound half bad. if this is a bubble back exhaust, t-stats are no easy to change. i had to do it in two step. whole thing won't go together in one shot, i used 3/8" copper tubing, cut to 1" pieces, slid on to bolts to act as bushings. using sealant, put t-stats, springs, bypasses, and black plastic plate on the motor and tighten. after glue sets up, remove bolts, remove copper bushings, now you can put the outside cover on w/o the other parts springing apart on you.

promotec · Nov 12, 2004

Re: Johnson 115 V4 1977 overheat

Hi badbillr Thanks for your feedback, yes headgaskets will be replaced, including overheat sensor (its melted) will also replace t-stats and waterpump, etc The t-stats arent a problem on my 77 115, it isnt bubbleback,I have already had the cover off them and there was pieces missing from what I think is the release/bypass valve which sits above the t-stat on my motor, my powerpack isnt watercooled i dont think it sits on top at the back of motor between the heads all the above isnt a problem as such the big thing i want to establish first is why there isnt any spark on any cylinders. I suspect the stator due to test results I got when using Joe reeves test tutorial for the stator the yellow and yellow/gray wires from the stator are giving no reading with a ohms meter and when testing the yellow wire with red test lead, and the black test lead to ground im getting a resistance reading which apparently I shouldnt get. Thanks for your input badbillr much appreciated. Kind regards Chris

Johnson 115 V4 1977 overheat

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