HELP 1994 Evinrude 115 E115TLERC New piston rings, carbs rebuilt just bought

chevegan

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Specs to know. I'm at 5500ft above sea level. Tank went through 3 hours at 25:1 break in fuel for new rings. I topped off with 87 octane ethanol free pure unleaded gas.

Hi all, I'm new here. I purchased a 1994 Sunbird corsair 170 with an evinrude 115 e115TLERC. The previous owner JUST had the VRO deleted, new piston rings with 1 new piston installed, and carbs rebuilt. It was done in Kansas where I found it and then run for 3 hours on the lake to tune properly. The tank was cleaned out and refilled since it was sitting prior to this. Ran fine with muffs but as soon as I got it on the water it started acting terrible. First off it was hell to get started. And that's after they used 140 degree decontaminate water through it getting it all the way to operating temp there at the lake.

Symptoms:
At first, right after launch, it would stall out at idle so I screwed the idle speed to raise it some which helped. But any wave or wake and it would 9 times out of 10 Stumble and die. OR go from running perfect to sounding like it was thumping and misfiring.

Did 3 WOT runs and first 2 times the OMC lean fuel alarm (i think) went off. That's a guess, basically after 15-20 seconds at WOT the alarm would go off. On the final WOT run it literally just died. But started and idled right back up again. I disconnected the alarm and just kept it low trolling rpm rest of the time

The bulb went flat more than a few times.

And above all it was CONSISTENTLY INCONSISTENT. Going from running like butter and firing RIGHT back up after stopping, to not starting or having a very very hard time then the lopey misfire sound would kick in, then in the middle of that go back and forth from running perfect.

Finally after 2.5 hrs on the water with this thing doing this the whole time (MAYBE 1.5hrs actual run time) after literally 30 min of trolling just fine it died when I put it in neutral and wouldn't start back up at all for anything. I used the trolling motor to limp back to dock.

Conclusions:
1)I first thought carbs may need rebuild but after looking at the work order he gave me when I bought the boat it shows that it had been done along with float adjustment on one of the carbs.

2) I bought a new fuel filter thinking MAYBE the new one clogged fast even after the tank cleaning just from debris?

3) I brought it from Kansas which is at maybe 3k feet above sea level to Colorado springs where I use the boat at around 5500ft above sea. Re-Jet?

I purchased a water pump kit just to do for good measure. Will install before next run out.

But the take away was how inconsistent it was. From running and idling fine 1 second to an absolute horror show the next. Cranking non stop, manually pumping bulb, neutral 2/3 throttle starts etc. And wake from boats absolutely would affect it depending on the angle it would hit at it seems.

Please help, I want this to be safe for my family. Thanks ahead of time
 

racerone

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Are you pushing the key in while cranking it over to start this motor ?
 

flyingscott

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The ball going flat is a serious clue. Is the arrow on the ball pointing towards the motor.
 

chevegan

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Actually to clarify not flat but soft no longer full. And no I don't push the choke in once hot.
 

flyingscott

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You don't have a lean fuel alarm on that motor. If the VRO has been deleted and unplugged there is no alarm for that. The only alarm left is the overheat. What alarm did you disconnect.
 

racerone

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New rings on 3 old pistons ?-----Explain " run for 3 hrs to tune it properly "------What are the compression numbers today ??
 

Tim Frank

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Did you try it on the water before purchase? i.e. have you ever seen it run well?

If you are over 5000 FASL that just is in the zone for needing slightly smaller jets.
I have no experience actually sizing them in this circumstance so you will need someone with experience to advise you on how dramatic a change to make. OMC dealer in the area.should be your go-to.

As suggested , baseline measurements are where to start....compression readings....spark verification ~ does spark jump 7/16" gap using a purpose built tester.
 

chevegan

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I honestly have no idea how to identify the alarm. 2 strokes are a new world to me so taking it 1 step at a time. There is a speaker behind the speedo, I pulled the wire after I made sure plenty of water was flowing through the pee holes.

racerone - The previous owner told me that he took it in to get new rings and the mechanic said one of the pistons had some marks on the top so replaced it for good measure? (I'll get back to you on the compression check)

Again I want to stress that with muffs it runs fine and even in the water it went back and forth from running like butter to misfire sound. I have lots of 4 stroke vehicle experience, but haven't messed with carbs for 18 years since back when I used to build drag cars when I was a teen.

My thoughts were I'm at 5500ft so it's automatically going to run rich and need re-jet (after holiday weekend going to call local shop to ask that one) And if the tank wasn't cleaned properly all it did was loosen debris which then COULD cause sticky floats if it got passed the filter, or probably clog the filter. But the filter would be a consistent issue, the floats are a better fit, what do you think?

I would love to know the idiosyncrasies of this engine so I can knock out the basic things first. I'm a big proponent of Occam's razor when it comes to diagnosing. Check the plug lol.
 

chevegan

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Did you try it on the water before purchase? i.e. have you ever seen it run well?

If you are over 5000 FASL that just is in the zone for needing slightly smaller jets.
I have no experience actually sizing them in this circumstance so you will need someone with experience to advise you on how dramatic a change to make. OMC dealer in the area.should be your go-to.

As suggested , baseline measurements are where to start....compression readings....spark verification ~ does spark jump 7/16" gap using a purpose built tester.

yes it ran very well, but with muffs on. It was a 16hr round trip with 2 kids in tow and I sadly had no time to take it to the lake there. Shop receipt states that they took it to bennington lake to make final adjustments and runs ok now.

Altitude plus 25:1 break-in equal to fouled plugs? Could that make it inconsistent? It's that darn inconsistency that's throwing me. Why run perfect then a wake from a boat throw it off and choke it out? Or shut it off then back on and it changes? I'm seriously scratching my head here. :noidea:

I'll hopefully have time to get to the compression check and spark check today or tomorrow.


Thank you everyone for your time helping me with this. :tea:
 

racerone

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They all just " bark and roar " on a hose.----Sound impressive and powerful.-------That has sold many a defective motor.
 

chevegan

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The compression test went as follows

Cylinder ---------Corrected for 7600' above sea level it reads
1-85 corrected 102.4
2-85 --------------102.4
3-81 --------------97.6
4-87 --------------104.8
 

Tim Frank

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If you are "using the boat at around 5500 FASL' " , why are you correcting compression to 7600 FASL?

Here is a rule of thumb from my archives....
"Main jet metering is of great imortance when operating at considerably varying altitudes for which the
following rule-of-thumb may be applied: change main jet calibration by 6% for each 1,000m (3280')
altitude variation. For example,( if ) normal main jet calibration at an altitude of 400m (1312') is 0115;
proper jet size for an altitude of 1400m (4592') is 0110"

That should give you an idea of where you are going....if you can figure out where you are. :)
 

flyingscott

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Get a different gauge and double check the compression. Your #s are not good for a rebuilt motor. Your #s indicate a 30 yr old motor that needs a complete rebuild. Corrected #s should be closer to 120 or above.Will the mechanic warrant it should be no reason not to if he stands behind his work. If it was mine It would be back at the mechanic who did the work. A couple of red flags on your motor stand out. The new rings old pistons is a huge no-no on crossflow motors. That motor should have been bored out on all 4 pistons and had new pistons installed. Why is your mechanic not helping you? OMC recomends a 10 hr break in period.
 
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chevegan

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I live at 7600 fasl. The main lakes I take it to are at 5200-5600 fasl. I did the compression test at my house thus the 7600ft. Should have specified that sorry
 

chevegan

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Get a different gauge and double check the compression. Your #s are not good for a rebuilt motor. Your #s indicate a 30 yr old motor that needs a complete rebuild. Corrected #s should be closer to 120 or above.Will the mechanic warrant it should be no reason not to if he stands behind his work. If it was mine It would be back at the mechanic who did the work. A couple of red flags on your motor stand out. The new rings old pistons is a huge no-no on crossflow motors. That motor should have been bored out on all 4 pistons and had new pistons installed. Why is your mechanic not helping you? OMC recomends a 10 hr break in period.

The mechanic is in Kansas where I bought it, 8hrs away from me. And frankly I really don't know exactly what he did to rebuild. I'll call when I get back home from out of town. All I see is what he wrote on the invoice. And really regardless with the numbers being as close as they are at about 100 psi corrected it should still run steady albeit weaker than factory I would think. Would that be a correct assumption? or am I out of my depth here lol.

Another thing I was considering is that the 87 octane was probably a mistake. Our base gas at altitude is 85. So I may be getting detonation issues as well with 87, maybe?

Also from an archived post here it F_R mentions "Yes, you can bore one, two, three, or more cylinders--don't have to do them all. In fact, it is sort of a waste to bore them if not needed. You might have to do another rebuild in the future and the material will be gone."

I just hope it wasn't honed over the blind holes of a 2 stroke. Again I'll find out when I get back home and get the number to call. Thanks again
 

chevegan

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So the boat shop threw parts at it.....fuel hose, plugs, filter etc. They did a compression test which came back at 90 for each cylinder uncorrected for altitude. They said same thing I did, engine runs fine until you put it in water then it runs "weird". They adjusted the idle to "high" so it won't die when shifted into gear.

Then they did a leak down test and 2 cylinders came back at 25%. But this still doesn't make sense to me. First a leak down on the cylinders of a 2-stroke? Second, IF it was done correctly it still wouldn't make any sense that the boat runs perfect at times then gets weird. Why would passing through wake have any effect on that?

Any suggestions?
 

racerone

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The 90 PSI is low !!----A leak down test will find air leakage so why would that not work on a 2 stroke engine ???-----Plastic bowls on the carburetors ?----If so , have they been checked for warpage ?
 
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