Somebody please help. 1978 Evinrude 115

[chasin-tails]

Ok guys, I got a problem. I will start from the begining. Two months ago I had problems with my engine not putting out enough power to get on plane, it would get up to about two thousand rpm and that was it. Everyone I knew told me it was this or that so I ended up changing the plugs, coils, power packs, and kits in the carbs.Needless to say that wasn't it so I called a boat shop. The shop told me it was my stator and they had one and if I'd bring it to them they'd replace it and I'd be on the wateer again. Well when I got it to the shop the guy asked if I had checked the compression and I hadn't (I was stupid I guess). He checks it for me and my #1 cylinder had 0, the other three had almost 120 on the dot. So it's time for a rebuild. I tear down the powerhead and see the #1 piston was kind burnt looking, crystalized, and missing some peices so at this point I need a bore job too. I send the block to the machine shop and get it bored thirty over ( what they said it needed). I order my service manual from iboats so I would know what the machanics know and order a rebuild kit with all the bearings, pistons thirty over rings, and all the gaskets. Now about a month ago everything thing is at my house and I come in from work ( I work offshore in Egypt). Me and my son bring all the parts inside my house on the floor with the service manual and start to put this thing back together. Everything goes together great and the powerhead is back on the boat in two days ready to go. I go exactly by the manual and do everything it says for the break in and I think I'm ready for the lake. The manual said to run the engine once in the water at idle for ten minutes so I run it at idle for about thirty minutes. Then the manul said to run at half throttle which is about 3000 rpm for ten minutes so I run it there for about thirty minutes making sure it's good. Ran great after that till I broke the throttle control box due to the linkage cable being too tight. So now I need a box. I call around and the closest one I find is three hours away so I'm on a road trip tyo New Orleans. I get back and install the new box and linkage cables and ready to go again. Well I get out on the water again and everything is going good but since I changed the linkage cables the throttle was a little out of adjustment. I shut down in the water and procede to adjust the linkage where it needs to be. After I'm finished and everything is back together here comes the problem I have now. I start it back up and the idle is fine but when I try to give it throttle it chocks out. Knowing the carbs have just been rebuilt the first thing I go to is the plugs. Well now the #4 plugs looks like it got hot and melted some. So I idle back to the ramp and on my way home. When I get home I change the plug and decide to pull the head just to have a look. Ok now the #4 piston looks like the #1 did to start with. Why is this happening. A friand of mine said I'm running to lean but I run 50:1 fuel and I changed nothing on the carbs from before I rebuilt it and it went from the #1 to the #4 and they are sepparate carbs on those cylinders. So if anyone can help me here I'd sure be greatful. Thanks and God bless......

 

[durban]

Re: Somebody please help. 1978 Evinrude 115

check the ignition timing at :WOT all the money you spent , you could have bought a 2nd\h power head . best of luck

 

[emdsapmgr]

Re: Somebody please help. 1978 Evinrude 115

You may not have repaired the original reason for the first powerhead failure. When doing a rebuild, some things to look for: 1. The water deflectors in the powerhead should be examined for condition and alignment. They can get out of position and can accumlate debris next to them which will restrict water flow around each cylinder. I'll post a picture of normal looking deflectors. If out of alignment, one cyl can internally overheat and never set off the hot horn warning. 2. Usually carb overhauls need to be done at the same time as the overhaul. The jets (esp the mains) need to be removed and visually inspected. If they accumulate any debris in them, they won't flow fuel and that one cylinder can run lean. 3. If that engine has original fuel hoses on it, they were not made to handle today's ethanol fuels. The hoses will break down and bits of black hose can lodge downstream in the jets-restricting them. 4. After starting up any new powerhead, it's best to warm the engine up and keep close watch on the temps of each cyl head. At least for the first hour. A laser temp gun is handy here. You want to see 143-155 degrees on both heads when at idle. 5. Your 78 has a telltale which will tell how the water pump is pumping. It does not indicate that one of the two thermostats might be stuck shut. (one for each head.) 6. You'll want to test both temp switches (one is each head) to make sure they will sound the hot horn if either head overheats. 7. You'll want to do a sync and link per the factory service manual. If that relationship between the spark advance and the carb butterfly opening is out of adjustment, it is possible to have the spark advanced too much when compared to how much the carb butterflys are open. Causing a lean condition. 8. This may sound odd, but check the carb roller. It should have a clear plastic/skin on the outside of the roller. If it degrades over the years, the skin falls off and the sync and link gets off.

 

[chasin-tails]

Re: Somebody please help. 1978 Evinrude 115

View attachment 163784You may not have repaired the original reason for the first powerhead failure. When doing a rebuild, some things to look for: 1. The water deflectors in the powerhead should be examined for condition and alignment. They can get out of position and can accumlate debris next to them which will restrict water flow around each cylinder. I'll post a picture of normal looking deflectors. If out of alignment, one cyl can internally overheat and never set off the hot horn warning. 2. Usually carb overhauls need to be done at the same time as the overhaul. The jets (esp the mains) need to be removed and visually inspected. If they accumulate any debris in them, they won't flow fuel and that one cylinder can run lean. 3. If that engine has original fuel hoses on it, they were not made to handle today's ethanol fuels. The hoses will break down and bits of black hose can lodge downstream in the jets-restricting them. 4. After starting up any new powerhead, it's best to warm the engine up and keep close watch on the temps of each cyl head. At least for the first hour. A laser temp gun is handy here. You want to see 143-155 degrees on both heads when at idle. 5. Your 78 has a telltale which will tell how the water pump is pumping. It does not indicate that one of the two thermostats might be stuck shut. (one for each head.) 6. You'll want to test both temp switches (one is each head) to make sure they will sound the hot horn if either head overheats. 7. You'll want to do a sync and link per the factory service manual. If that relationship between the spark advance and the carb butterfly opening is out of adjustment, it is possible to have the spark advanced too much when compared to how much the carb butterflys are open. Causing a lean condition. 8. This may sound odd, but check the carb roller. It should have a clear plastic/skin on the outside of the roller. If it degrades over the years, the skin falls off and the sync and link gets off.

Thank yall for all the good advice. I will check this as soon as I get home and see what I can figure out. The water flow issue you were refering to is the grooves around the outside of the head right? I know I cleaned those really good. They were looking bad before the rebuild. The carbs had just been rebuilt before the powerhead may be with 30 min worth of running. I pulled the jets and made sure they were clear and also blew through the bowl. Might not have been enough though. I had replaced both thermostats when rebuild was done also. Should I pull them out just to check? My telltale is flowing water. I know that ain't a sure thing all the time. I am going to have to pull it all the way back down just to replace the one piston, I will go back through it. Carbs might be out of adjustment. The book tried to tell me to adjust the jets but I think mine has the ones you screw all the way in and that's it. You might know more about this one?

 

[emdsapmgr]

Re: Somebody please help. 1978 Evinrude 115

The jets in the carbs are fixed in size. Usually they do not need to be changed from what the factory originally installed. I'd pull the jets out of the carbs again-paying special attention to the main jet that feeds the damaged cylinder. Visually check to make sure it is completely open-not restricted.

 

[Bob_VT]

Re: Somebody please help. 1978 Evinrude 115

OFF TOPIC

Break your question into multiple paragraphs. Many people will not read a huge block.