sticky piston rings on 1978 115 evinrude

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

they didnt diagnose a frigin thing ....that just the way boat mart in red deer is , if u need a themostate ..they will rebuild your engine. these guys have the foot from the 77 motor i just bought off a fellow in red deer and they told him that they cant rebuild his seised lower gearcase. starting to get pretty confused

 

[Faztbullet]

Re: sticky piston rings on 1978 115 evinrude

Sell the 77 and get as much of your money back... rebuild the 78 model if block is good shape and you could have rebuilt it for $700 yourself.

 

[SparkieBoat]

Re: sticky piston rings on 1978 115 evinrude

Thanks Faz..I thought the foot change was in 79. I didnt know it was 78. My option would be to buy a good use motor already running or at least has good compression. I see them constantly for around $700, and I would get at least an 80s model, I am not a fan of the hydro assist shift motors, the new style is superior in my opinion. I see lots of 90s models for around $1200 less if they need work, carry a hot battery, plug socket, spark gap tester and a compression gauge with you when you go to look at a motor.

 

[ezeke]

Re: sticky piston rings on 1978 115 evinrude

Why not slow down a bit and see what is wrong with the 1978 engine. Take the cylinder heads and the bypass plates off and you should be able to get an idea - that will cost you four gaskets.

The 1979 engine is different and so is the 1977, so you have a narrow window of options with the 1978 motor.

The 1977 140 parts will work. Some of the 1977 extra long 115's were set up similar to 1978.

 

[SparkieBoat]

Re: sticky piston rings on 1978 115 evinrude

thats good to know Ezek. not to piggy on this guys thread, but your answer may interest him for future use, are the 79-91 motors pretty much interchangeable? This information can really be helpful if you are deciding whether or not to put a lot of money/time into a motor that may be difficult to find parts for...he said his gearcase is froze up, so my thought would be why fix the motor and then not be able to find a usable gear case, they are very pricey to rebuild. That was why I suggested maybe looking for another good used 80s model motor.

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

Why not slow down a bit and see what is wrong with the 1978 engine. Take the cylinder heads and the bypass plates off and you should be able to get an idea - that will cost you four gaskets.

The 1979 engine is different and so is the 1977, so you have a narrow window of options with the 1978 motor.

The 1977 140 parts will work. Some of the 1977 extra long 115's were set up similar to 1978.

Your right , and thats what im going to do is a good inspection of the 78 motor that came with the boat. the only reason i bought the 77 motor is the fellow that was selling it said that his powerhead was good [as mine was not],and his foot was siezed [but mine was not],so i mistakingly presumed that i could swap things over and save a bit of time and grief. If i cant do the swap i will do the piston, rings , carb and water pump, thanks for your help guys.

 

[ezeke]

Re: sticky piston rings on 1978 115 evinrude

The 1979 and newer engines blocks have the newer, cast-in mounting and uses a different crankshaft, among other things. From 1979 on, the 115 crossflow blocks are very similar and that includes the ones used in the 115 TurboJets from 1994 through 1997.

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

The 1979 and newer engines blocks have the newer, cast-in mounting and uses a different crankshaft, among other things. From 1979 on, the 115 crossflow blocks are very similar and that includes the ones used in the 115 TurboJets from 1994 through 1997.

so with this 78 crossfire that im going to do the rings and etc, its not a very interchangeable motor , do you think any thing on the 78 would accepet any of the parts from the 77 ,eg coils , carbs, starter, anything.

 

[ezeke]

Re: sticky piston rings on 1978 115 evinrude

If you take the 1977 carbs as they are and do not change the orifices, then they will work, but that is not necessarily a good idea. I would try to find newer carburetors with a primer solenoid and get rid of the choke plates. The carburetors that you have are among the easiest to rebuild so unless they have been damaged, there should be no need to change them unless you want to get rid of the choke system.

Some ignition components could work, but again, it's a step backwards. Some parts like the flywheel are not compatible at all even though they look much alike.

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

If you take the 1977 carbs as they are and do not change the orifices, then they will work, but that is not necessarily a good idea. I would try to find newer carburetors with a primer solenoid and get rid of the choke plates. The carburetors that you have are among the easiest to rebuild so unless they have been damaged, there should be no need to change them unless you want to get rid of the choke system.

Some ignition components could work, but again, it's a step backwards. Some parts like the flywheel are not compatible at all even though they look much alike.

thanks again, i just finished pulling the heads and had a good look, the cylinder walls look good , mabye a little shine with the cylinder hone to get the varnish off but other than that the block looks good , whew, top pistons are sloppy indicating worn rings?. tomorrow going to pull the carbs and crank case off and see what i can see. hopefully its all good.

 

[bktheking]

Re: sticky piston rings on 1978 115 evinrude

How did the gasket look? Post pics of possible.

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

How did the gasket look? Post pics of possible.

hi bktheking, the gaskets were in great shape no signs at all of any leaks. the cylinder that was reading 30 on the comp test did have very slight scoring and the piston was sloppy, which maybe tells us that its worn piston rings? both bottom pistons, one with 101 comp, the other with 95 comp seem fairly tight no scoring on any of the other cylinders, going to pull the carb and crank case off and pull the pistons and replace pistons along with the rings and bearings.

 

[bktheking]

Re: sticky piston rings on 1978 115 evinrude

I think you'll be getting into more than just rings, overbore and oversized piston and rings if there is any slop.

You might be better off fixing the one with the bad lower unit.

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

I think you'll be getting into more than just rings, overbore and oversized piston and rings if there is any slop.

You might be better off fixing the one with the bad lower unit.

no dont think so , rotated the engin and seen the rings in action , they are badly worn

 

[ezeke]

Re: sticky piston rings on 1978 115 evinrude

I would recommend that you not waste too much time on the 1977 motor if you want to keep the 1978. The 1977 has a totally different gearcase and shift system, different midsection, totally different water pump, different powerhead and ignition system. The newer 1978 and up PT&T systems will work on the 1978, but not the 1977 PT&T.

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

I would recommend that you not waste too much time on the 1977 motor if you want to keep the 1978. The 1977 has a totally different gearcase and shift system, different midsection, totally different water pump, different powerhead and ignition system. The newer 1978 and up PT&T systems will work on the 1978, but not the 1977 PT&T.

now that you guy have made me a whole lot smarter on this , again thank you very much, i intend to pull those piston , rings ,jets and pumpon the 78. with the 77 mabye in time i will have the siezed gearcse rebuilt or i will tear it down myself . i cant lose anything by playing around with it.almost forgot to ask you, the bore on my 78 [according to this clymer book] 3.500 in,after honing the varnish out do you think i should put in the next size piston and rings,do you know what the next size up is.

 

[bktheking]

Re: sticky piston rings on 1978 115 evinrude

You would have to put the next size pistons and rings in for sure, it wouldn't be standard bore anymore.

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

You would have to put the next size pistons and rings in for sure, it wouldn't be standard bore anymore.

that what i thought , standard bore size is 3.4995-3.5005 in. the piston has very little slop , but i guess it doesnt take much

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

pulled the carbs of , the cylinder with the low comp had a piece of grass or seaweed, i dont know what it was , but for sure that jet was blocked . so that would cause the lean cylinder condition [slightly scored ,worn rings].????

 

[trackhoe1]

Re: sticky piston rings on 1978 115 evinrude

You would have to put the next size pistons and rings in for sure, it wouldn't be standard bore anymore.

had the cylinder walls checked and they are all right around 3.49 . so that means the rings are gone and i can still use standard size pistons?????????. have you ever replaced the piston with the powerhead still in place . the only reason i ask is i have everything off to get at the connecting rods .