'96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

[crappie_condo]

Just had this sucker rebuilt because of a broken ring. I put the first 10 hrs. on it to break it in and the idle was OK. During the 11 to 20 hr. mark, the idle is getting worse. Took it back to the rebuild shop and they found a recirulation hose had popped off. Fixed the hose problem, but still not much change in the low idle sputter in gear. Also tilting the engine up and down affects the idle. Better idle up and worse down. It has metal bowls on the carbs. The Wrench has had the carbs and fuel pump off a couple of times looking for problems, but nothing yet. I am leaving it there til next week because he is going deeper into the front of the motor to double check a seal replaced during the rebuild. When we were doing a Lake test he popped off the bottom 2 plug wires while running and it did not affect the RPM as much as the top 2 cyl. The engine seems to load up at idle. Any input would be appreciated.. Thanks in advance...

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

bump

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

bump

 

[Solittle]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

Did you or the shop pull the t-stats? OMCs don't idle well unless they get to operating temp. Tilting the engine results in small change in the fuel in the float bowl.

 

[OBJ]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

Pulling the plug wires off with hardly any change in rpm would almost indicate an ignition problem. Cylinders not get the right spark or none. Putting a timing light on the plug wires might tell ya' something. And just for grins, when your out in the boat, grab the wire bundle where it goes into the engine and pull up and down on it to approximate the tilt of the engine. See if it makes any difference.

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

Thanks for the replies. The t-stats are installed. I will definitely try moving the wire bundle around to see what happens. Is it possible for the ignition to be weak at idle and OK above idle to WOT?? Here is another little interesting thing after the rebuild, the sparkplugs are slightly contacting the pistons (all 4). The Wrench actually pointed this out to me. He said, " I never had that happen in any rebuilds before". He said I will need to run center fire plugs. I assume the block and or heads have been resurfaced or decked one too many times?? Well, I will be calling him today to see what's happening. I'll post the results, thanks again.....

 

[Dhadley]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

STOP!!!!!!!!!!!!!<br /><br />DO NOT RUN IT ANYMORE!!!!!!!!!!<br /><br />What plugs are in it now?

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

Dam'n that was a quick response!! Last time I had it at the shop, he put a set of centerfire NGK's in it. After the rebuild, it had the factory QL82C in it (the ones contacting the pistons). Hopefully, I'll have some news later today. What do you think Dhadley?? Did I get a screwed up rebuild??

 

[OBJ]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

What Mr. D. is saying is, if the pistons are contacting the factory plugs, then something really bad is going on. Do not start the engine until the problem is resolved. Changing plugs to center fires dosen't resolve the problem. How many times have the heads be shaved and why?

 

[Dhadley]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

Exactly. And get those KGB -- er....NGK's out of that OMC.<br /><br />Now, the ones that hit the pistons -- were they definately QL82C's or QL82YC?

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

I'm not sure how many times the heads have been shaved. I bought this boat in May '04 and have not had any major engine work done to it. I had a piston ring break in one of the cyl. and this is where I'm out now. I will have to re-verify the champion plugs that were installed right after the rebuild. Talked to the Wrench today, he said everything internal, seals, gel seal looked good. He said if the fuel is leaned out at idle. (I.E. lowering the fuel level in the bowls) the idle picks up and is solid. He will be trying another set of Carbs next. The piston to spark plug contact is exactly like this post>>> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=016544#000000 <br />Thanks again for the replies, I'll keep updating..

 

[OBJ]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

How did it idle before the rebuild condo? Were the carbs rebuilt as part of the rebuild? They should have been.

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

The idle was fairly solid, but not perfect before the rebuild. Yes the Carbs were overhauled as part of the rebuild. Last update, the Wrench put a different set of Carbs on and said it fixed the idle problem. He is taking it to the lake on Wed. to double check it on the water. I'll keep updating.... Thanks again..

 

[Dhadley]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

I'm not sure how many times the heads have been shaved.

You dont want to "shave" them at all. If they've been cut, replace them. Especially if you even think they've been cut more than once. Period.

 

[Crappie_Fan]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

The mechanic should have inspected everything before the rebuild right,like deck height and head thickness, etc... I would be a little spooked if I had a engine rebuilt and the mechanic made it completly through the rebuild and never checked things like this to even see if it was a good canidate for a rebuild right?

 

[Dhadley]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

Another thing is, did the rebuilder tell you why the ring broke? And what was done to insure that it doesnt happen again?

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

I'm pretty sure the ring broke from coking. I pulled the head and posted the pics here after it happened. http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=029158#000002 <br /><br />The VRO was disconnected when I bought the boat, so it might have had prior damage from no or low oiling. Also the engine height setup with a 19 pitch prop was not correct either. There was definitely some lugging going on with the previous owner. I don't know if the block or heads have been shaved, I was just assuming because of the tight clearance between the pistons and spark plugs. He used forged pistons on the rebuild and did a Cyl. leakdown test (<1% all cyl) with me watching. I'll try to get some part numbers of the pistons and other stuff replaced. Hopefully I'll get a update today!

 

[Dhadley]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

The part number on the forged pistons will be the 3173 series. Thats good. If he used the QL78YC plugs that would explain why they hit. If he used any Champion plug without the Y and they hit, thats a problem. I would not run the motor any more until its verified why the plugs hit.

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

OK P/N for pistons installed - 3173P2. Plugs installed after rebuild QL78YC. Dhadley - you are right on!! It was a relief for me to find out about the plugs!! Well, here is the short story after getting it back on Friday. Took it to the lake right away, NGK plugs (B8HS 10) installed, the idle was good and it ran well. After some research on the plugs found I should be using QL77JC4. Sunday, installed QL77JC4 plugs and went to lake. The idle was back to the same old sputtering and dying thing again. Re-installed the NGK's No Change.. Put in some gapless / centerfire NGK plugs and it seemed to idle somewhat better. AHHHH!!!! I'm about ready to put a smallblock Ford in this Mugg and be done!! Monday update, hooked up my portable gas tank going back to the dock and the idle was good. My portable has its own primer bulb on it. I don't know, could I have some wierd igntion thing going on or what?? I also noticed at idle the engine will sometimes skip or act like it dropped a cylinder for a split second. I'll keep running off the portable and see what happens. I think as long as I have this motor, this post will continue to update!!!

 

[crappie_condo]

Re: '96 Johnson 115 crossflow sputters at idle after powerhead rebuild??

Tuesday, took it to the lake on the portable, still acting up. Is it possible to have a low speed (idle) ignition problem, but OK above idle??<br /> It still acts like it's dropping a cyl. every now and then at idle and then it picks back up. This motor should be able to idle in gear for more then 1 or 2 minutes without reving it up right??? Not sure where to go from here???