'97 115 won't idle and spits all of a sudden

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Was just outside (in between rain showers) and ran it to get it up to temp so I could do a compression test, it fired right up and ran fine with the fast idle lever keeping it at about 1100-1200, sounds totally normal, once you pull back on the fast idle lever it drops to about 4 or 500 in that "notch" and you can hear it struggling, and then in Neutral it drops more and will idle, but just barely and definitely sounds like at least two cylinders missing.

I figured I'd pull the cover off the carbs so once it warmed up I could try spraying pre-mix down the carbs. After running for about 5 minutes I looked in the carb throats and there is greenish white milkshake looking stuff all inside the front of the carbs, which I know is oil mixed with water, it was actually dripping from the top of the inside of the carbs too.

Like I mentioned it is a rainy and really humid day here, is this just from the moist/humid air being pulled into the carbs when it's running and mixing with fuel being pulled into the carb throats? I should mention that I did not spray anything down the carbs, just letting it run and noticed this milkshake in the carbs. My next step is to dump my fuel/water separator and see what the fuel looks like.

What do you guys think about the greenish/white milkshake in the carbs? I can grab a pic if it will help.


Thanks.

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Bump^^

Just trying to see if any pros think this milkshake in the carbs is a problem.

Thanks.

 

[ezeke]

Re: '97 115 won't idle and spits all of a sudden

Very common with ethanol to have water in the float bowls. Full-sized water separating filters help if you dump them occasionally. Try flushing the float bowls and see if there is a change; just remove the drain screws one at a time and squeeze the primer bulb - catch the fuel in some old rags.

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Thanks ezeke. I don't see the green milkshake color down the throats, just all around the carb openings and it's dripping from the top of the carb openings too, saw a little when I popped the carb cover off, but it got worse the longer it ran. Wasn't sure if it was just from really moist air coming into them and mixing with the 2 stroke in the fuel or water in the actual fuel, I guess water in the fuel isn't too hard to conceive with ethanol.

I will dump my fuel/water separator and re-fill it with good fuel, then pop the carb drain plugs and pump the primer bulb, like you said.

What exactly do the carb drains look like on my carbs, are they a big bolt looking thing? Sorry still learning, thanks again.

 

[bob johnson]

Re: '97 115 won't idle and spits all of a sudden

I think that green stuff is the left over oil residue from oil mixed gas

i had that on my airbox cover contantly..they have a hose that takes all the stuff that drain into the airbox and feeds it back into the motor..

so they know it happens...

since I have cleaned up my carb connections( i had a few little leaks here and there...slight) I dont get as much of that residue..

why it is milky i dont know...that COULD be from teh water or dampness..

I think whenh you tilt the motor you could get some gas coming out of the carb and draining into the openings...

if you drain your carbs like mentioned and it has the milky solution, you then know you have issues

i would worry about the oily residue on the carb fronts....if the gas in the carb bowls is clean.....

you shoud have taken the chance to spray gas in the carb throats!!!!!!!!!!! while you were there!!!!!!

so you didnt even do a compression check???

I know that those carbs have a flaw.... on the starbord side of all the carbs is a passage that is plugged by a brass ball

all my carbs leaked out of that spot..

seesm the opening was a little too large for a nice press fit on the brass ball and the previous guy put some kind of sealer on it...well the sealer broke down

thus i was always having that greenish film( gas evaporated and left the oily residue

if you have a lot...you might be leaking gas someplace

bob

 

[ezeke]

Re: '97 115 won't idle and spits all of a sudden

Thanks ezeke. I don't see the green milkshake color down the throats, just all around the carb openings and it's dripping from the top of the carb openings too, saw a little when I popped the carb cover off, but it got worse the longer it ran. Wasn't sure if it was just from really moist air coming into them and mixing with the 2 stroke in the fuel or water in the actual fuel, I guess water in the fuel isn't too hard to conceive with ethanol.

I will dump my fuel/water separator and re-fill it with good fuel, then pop the carb drain plugs and pump the primer bulb, like you said.

What exactly do the carb drains look like on my carbs, are they a big bolt looking thing? Sorry still learning, thanks again.

The drain plugs are on each side of the float bowls of the crossflow carbs. The high speed jets are aligned with and just behind the plugs.

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Thanks ezeke, I will drain the bowls and pump fresh fuel through them and see what happens. Do I need to drain fuel from both drains on each carb, or will one drain on each carb do it?

Bob....yeah the green residue is definitely oil, I know there is always residue left over after the engine runs, so that didn't surprise me to see oil in there. It was just when it started running how the oil/gas mix turned milky that surprised me. The weather here today was like being inside of a cloud though, like 90% humidity and rainy/misty all day, so I wasn't sure if it was just really wet air being pulled into the carbs, or if it was actual water in the fuel/oil mix that was making it milky.

This week I will do everything, drain carbs, do a compression check, test spark and timing. Haven't had any time since this happened.

Thanks for the all the help guys, I really appreciate it.

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Quick question, when you dump out a fuel/water separator does any water it has collected come out as well, or will water stay trapped in the filter and only fuel come out?

Dumped mine, fuel is clear and clean, no water on the bottom of the glass jar and no separation at all.

 

[ezeke]

Re: '97 115 won't idle and spits all of a sudden

The water separates by gravity and will settle to the bottom of the container in time as petroleum products float on water. When you occasionally dump the filter, any water will be drained out.

Water in the float bowls of the carburetors must be flushed out as it will not be pulled out through the engine and removing the carburetors is generally not necessary.

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Well, here's the culprit:

Port top cyl - 120psi

Port bottom cyl - 120psi

Starboard top cyl - 65psi

Starboard bottom cyl - 125psi

Dumped some two stroke down the Starboard top cyl and re-tested, it went up to about 90psi.

So I guess I can assume at the least a stuck ring, possibly a broken ring? Absolutely no metal on the plug and when I look down the cylinder with a flashlight I don't see anything that looks abnormal, then again it's tough to see down there.

What now??

 

[bob johnson]

Re: '97 115 won't idle and spits all of a sudden

Sounds like you may have dropped a cylinder; do a compression test, then the spark test. Check your spark plugs.

Is it a crossflow or a looper? What's the model number?

good call.....on little info.....

may have other issues as well........

step by step you got to diagnose these things.....

now what caused it?????

bob

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

I think I always knew it in my gut, I just didn't have a good feeling about this.

With these crossflow carbs, is it possible to lean out on one side of the carb and not the other? I would think so since it's a two barrel carb.

The top port cylinder that runs off the same carb has perfect compression, but then again that's a separate barrel.

I'd really like to figure out the cause, even before getting anything repaired.

Is it possible for a ring to just stick and not be creating any compression or is that wishful thinking and more than likely a ring broke?

 

[bob johnson]

Re: '97 115 won't idle and spits all of a sudden

I think you have carb issues as well, which might have caused your problem

I think a V4 will idle with one plug wire pulled off an other wise perfect motor....

that isnt NO compression, you have some percentage it could be a carboned up ring..or a stuck ring...chances are....it is worse though


my buddies 1987 88 special ran his 28 foot pontoon about 20 mph to and back from the dealer on the lake( about and hour)

the dealer told him he had no compression in one cylinder and low in another..

well he bought a used motor and went back to the dealer to have him install it...

i asked for the old motor!!

i got the controls and harness and motor( he went with a merc)

because I figured the guy was laying to him...the motor seemed to run fine..

he originally had trim issues...but told the guy to check it all out.

but sure enough when i did a compression test, I got a big ZERO in one hole!!

point is, even with low compression your motor could run fine...so your issues are MORE than one low cylinder compression

good luck

bob

 

[ezeke]

Re: '97 115 won't idle and spits all of a sudden

I think I always knew it in my gut, I just didn't have a good feeling about this.

With these crossflow carbs, is it possible to lean out on one side of the carb and not the other? I would think so since it's a two barrel carb.

The top port cylinder that runs off the same carb has perfect compression, but then again that's a separate barrel.

I'd really like to figure out the cause, even before getting anything repaired.

Is it possible for a ring to just stick and not be creating any compression or is that wishful thinking and more than likely a ring broke?

Here's the best answer to the question of why the crossflow rings hang: http://forums.iboats.com/showpost.php?p=1351029&postcount=5

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Bob...I was kind of thinking the same thing, since when I bought this boat, I went on the test drive and it started and idled perfectly, went out and it wouldn't get on plane right and wouldn't get any higher than like 4700 RPM WOT.

Went back and I took the cover off and saw a broken plug wire/boot (oddly enough on this same cylinder), fixed the wire and went back out, and it ripped up onto plane and ran 5400 WOT. I changed props right after I bought it and got the WOT RPM up to 5700.

Point being that it idled pretty good with a fully dead cylinder when that plug wire was off, so I guess I do have another issue, on top of the low compression.

By the way I did do a compression test before I bought it, and that cylinder was fine then, in 2007.

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Just out of curiosity, what number cylinder is the Starboard top cylinder? #1?

 

[ezeke]

Re: '97 115 won't idle and spits all of a sudden

Starboard top is #1. The cylinders are numbered in the order that the rods attach to the crank, top to bottom, and that's also the firing order.

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Well the head is off, and it's a snapped ring or rings alright, and it did a number on the piston and head. The cylinder itself escaped any real damage, you can still see the cross hatching on it and it looks pretty good. Some very, very slight scoring in one spot.

The guy working on it for me,(a guy I know), is a top OMC tech on the island, and he seems to think he can hone the cylinder and then make up the slight additional space with slightly bigger rings on the new piston. He also thinks the head "may" be able to be machined, but possibly need a new head. To me it looks like I will need a new head, that looks like a lot of damage to me.

Here are some pics, let me know what you guys think. Also let me know what you think about all the carbon/coking on the pistons. The guy says this is pretty heavy carbon build up, no doubt what led to the snapped ring, as ezeke and others have mentioned. You can see on the bad piston it almost looks like it's dripping down the side of the piston.

The guy asked what kind of oil I have been using, I usually use Pennzoil syn blend, and last season I used Yamalube all season. I mention I've been running Super Tech this season and he cringed. Obviously he doesn't think Super Tech had anything to do with this, and neither do I, but he didn't have very good things to say about it.

I told him that when I got this engine it was propped to run like 5100-5200 WOT RPM and who knows how long it was like that, could have been the 10 years prior to me buying it, and so it was probably lugged for a long time, and he said that probably was a huge cause of all this carbon, which from reading this site I would think as well. I have it propped to run about 5600-5700 now, but I guess it was too little too late.

 

[bob johnson]

Re: '97 115 won't idle and spits all of a sudden

I told him that when I got this engine it was propped to run like 5100-5200 WOT RPM and who knows how long it was like that, could have been the 10 years prior to me buying it, and so it was probably lugged for a long time, and he said that probably was a huge cause of all this carbon, which from reading this site I would think as well. I have it propped to run about 5600-5700 now, but I guess it was too little too late.

I would be suprised if 5200rpm on a crossflow would be considered LUGGING it..

but you dont know the history... props can come and go easily over the years...

personally i would like more than 5200 rpms. but surely it cant be BAD for that engine..lugging is like 4600 and lower...

good luck on that rebuild...going through one myself right now..


bob

 

[MakoNY]

Re: '97 115 won't idle and spits all of a sudden

Do you think all that carbon was caused by just years of not being decarbed maybe? Does that look like a lot of carbon? I'm not experienced enough to know if that's a lot or a little, I was told it was a lot.

I thought anything lower than 5500 WOT was lugging it, but I guess 5200 probably wasn't enough to cause that much carbon.

Do any of you experts think that head can be salvaged, or should I expect to need a new head? Also why aren't the inside of the heads/combustion chambers full of carbon? I figured they'd carbon up too, but they look clean as new.

Thanks.