200 Ocean Runner #3 cylinder is dead

[bgrimes422]

Been reading a long time but first time asking.
I have been working for 2 weeks on this motor and about to pull both hairs out. J200TXERK 105 psi on all but #5, 100 psi on it. Good spark with spark check on all. Have been through carbs 3 times and just installed a set of 225 hp carbs just in case I still missed something. Have changed out the timer base no effect with an old one I had. New Coils - no effect. New plugs - no effect. At Idle, I pull plug wires off and all but #3 respond. When I go and run it it turns 5800 rpm wot except sometimes when #3 kicks in and then it bumps against the rpm limiter (I have ordered a new prop). When #3 does kick in it only last a couple hundred yards at the most and the drops back. I have checked all electrical connections, checked for vacuum leaks in the block. I have ordered a new power pack but I am guessing that isn't the problem because I have good spark on #3. The plugs look about the same except #3 looks more washed but if it isn't firing correctly it would. The only thing I can think of that I could still be missing is a water leak into #3 cylinder and I have ordered new head gaskets to check that, but it isn't loosing any compression. Can anyone think of anything else I might be missing? I consider myself a pretty good outboard mechanic but this motor is driving me crazy.

 

[dingbat]

The plugs look about the same except #3 looks more washed but if it isn't firing correctly it would.

Misfires and steam cleaning look entirely different.

I fought water in the cylinders (leaking head gaskets, multiple) on my 200 for 3 years before finally giving you and swapping out the power head.

Remember, it's sucking the water on the down stroke. A leaking head gasket could have little to no effect on compression.

 

[bgrimes422]

I took the heads off yesterday. Light carbon browning on all the cylinders, including #3. Disappointing. I will check the heads for flat today but from the color it looks like I didn't have a water leak. There goes one of the hairs I had left on my head. I'm down to one and still don't have any answers. I should have also mentioned I put a set of boysen power reeds in and while it idles a little better it didn't change anything with #3. I also changed all the re-circulation fittings and check valves. I guess all I can do is wait for the power pack and pray. Never seen anything like this before.

I do have more idle problems with the 225 carbs but I haven't taken the time to adjust/tune them out yet. Also, when I get the heads back on I want to run it wot again to see what happens. When the 200 carbs where on I swapped the plastic portion of the carbs with no change. I also sprayed carb cleaner through the passages on the carb bases and ran torch tip cleaners through the passages and it all looked clean, but I never swapped the carb bases. I did synchronize the carbs each time. Is there something else in the carb base that I could be missing by not swapping the bases? I'm just grasping at any straw I can think of now.

 

[daselbee]

Carb bases? You mean the throttle bodies?

If you took 200 carbs off the motor, left the throttle bodies in place, and bolted on 225 black carb bodies....UH OH. You cannot do that.

With these loopers, the carb ASSEMBLY consists of the black carb body AND the throttle body that they bolt to.
You cannot mix and match like what I think I read above.

There are major differences, the biggest one being that the 225 venturi throat is bigger than the 200. If you have a big throat in the carb, and a smaller throat in the throttle body, you have a "step" in the air flow right where they bolt together. That motor will run lean due to the disruption of smooth air flow thru the entire length of the carb bores.

This is probably not related to your #3 problem, but YOU CANT DO THAT.

 

[daselbee]

Regarding the #3 problem, try spraying premix into the affected carb. See if #3 now contributes.

If you have NOT had those throttle bodies off, and have not cleaned the calibration pockets, then it is likely that #3s cal pocket is fouled up.

To get an idea what I am talking about, remove the small metal plate on the side of the throttle body on say for example #2, top STBD carb.
(You Do know that the carbs are "crossed" on these engines, right?)
Cyl #1 is top STBD, but the carb for it is top PORT. Likewise with the rest of the cyls.

Look in the cal pocket with a flashlight, and you will see 5 very tiny holes that pass thru into the throttle bore right at the location of the butterfly.

If those holes are clogged....bad idle, no idle on any one cylinder if really bad, lean sneezing, sneezing to stall, etc.

I say try #2 first because you can get to it easily without taking the throttle body off. You cannot get to #3 easily.
Look in there and eyeball the holes I am talking about. You will see.

 

[bgrimes422]

I have had the throttle bodies (carb bases as I was calling them) off several times and have sprayed carb cleaner through the tiny holes as well as uses a torch tip cleaner to probe them. I am using the 225 throttle bodies with the 225 carbs and vice-versa. I haven't tried spraying mix into the affected carb but I have put my hand over the carb for a quick second to bring excess fuel up. When I did it seemed to choke the engine down a couple hundred rpm for a few seconds and I am attributing that to the excess fuel crossing over to #4 cylinder through the re-circulation system and choking it. It did not seem to change #3. I will try a spray bottle with mix because it would be less excess (good idea) when I get the heads back on. Waiting on head gaskets to come in now. In the mean time I might take the 225 carbs and throttle bodies off one more time and go through them. The head gaskets and the new power pack should both be here before this weekend so I expect to get a lot of work done then. Thank you guys for your ideas and please keep them coming. I'm sure with all these smart minds we will eventually figure it out. Thanks again.

 

[bgrimes422]

The head gaskets just came in along with the power pack. Tomorrow I will pull the boat out so I can remove the lower cowling to properly torque the head bolts and I will change the power pack. I just rebuilt the carbs again. Didn't find anything that would be a problem but I can now say for sure the carbs are spotless and up to factory specs across the board. Since I have yet to find a problem, can anyone tell me what happens when you break a crank seal ring? Does the motor show a compression loss? Do both connecting cylinders show a problem? I know I have never heard of breaking those seal rings but something is wrong and I sure can't find it.

 

[dingbat]

I will not bore you with the story, but take a can of carb cleaner with the straw and shoot it in each idle jet with the motor off.

My issue turned out to be a hair line crack in the carb body. Not really visible with the naked eye but very apparent when carb cleaner came shooting out the crack

 

[clemsonfor]

But didn't it miss with both sets of carbs/car bodies?

 

[bgrimes422]

I did shoot carb cleaner through the throttle body bores yesterday and probed them with torch tip cleaners. They looked good and carb cleaner sprayed out the holes where it was supposed to. #3 cylinder was dead at idle with both sets of carbs and no amount of adjustment on the bleed screws seemed to help that. I went to put the power pack on and found something strange. There were no studs at the back (I had to look at the book to figure it out) to hold the power pack down. Instead, there were bolts. The ground for the power pack was grounded to the voltage regulator, that's what clued me. It should be a good ground and I wouldn't suspect that as a problem, but I went ahead and ordered the correct studs anyway. The head gaskets that arrived were the wrong head gaskets, so that is going to put me back a few days. Please keep the ideas coming. I have a few more days now to think on this before I get back at trying to fix it. By the way, I live out in the boonies so when I order stuff it is on the internet and I have to wait for it to arrive. Thank You everyone for ideas.

 

[dingbat]

I did shoot carb cleaner through the throttle body bores yesterday and probed them with torch tip cleaners.

Not the throttle bodies, the carb themselves. Crack carbs are not all that uncommon

 

[bgrimes422]

dingbat, I could see that as a possibility with the plastic bodies, but I did spray all the passages and didn't notice anything. And since I exchanged the carbs more than once on the engine and it didn't change cylinder 3 not hitting or the other cylinders were hitting, I think that should pretty much eliminate that as a possibility, don't you? I really believe the problem has to lie somewhere besides the carbs since I have swapped the carbs among themselves and even swapped back and forth between a set of 200 hp carbs and a set of 225 hp carbs, throttle bodies and all without any changes to cylinder 3.

 

[clemsonfor]

dingbat, I could see that as a possibility with the plastic bodies, but I did spray all the passages and didn't notice anything. And since I exchanged the carbs more than once on the engine and it didn't change cylinder 3 not hitting or the other cylinders were hitting, I think that should pretty much eliminate that as a possibility, don't you? I really believe the problem has to lie somewhere besides the carbs since I have swapped the carbs among themselves and even swapped back and forth between a set of 200 hp carbs and a set of 225 hp carbs, throttle bodies and all without any changes to cylinder 3.

Ok so the perose I responded was not the OP (you) that was someone else saying the issue was a cracked carb. I was like it followed a completely different set of carbs so that couldn't be the issue??

 

[alanfox55]

Just going to throw this out there. I had a 30 hp single carb motor I rebuilt the carb and cleaned it twice. Looked good and clean to me but would not idle below 1400 RPM. Finally I soaked it for eight hours in Yamaha carb cleaner and that fix the problem. After that it Idled perfectly and ran perfectly.

 

[Faztbullet]

Make sure your working on correct carb as that motor has X flow intake...the carbs on right side feed the left bank and vice versa.......so #3 looking at carbs will be middle left.

 

[bgrimes422]

No Title

Yea, I follow that it is cross flow on the carbs, but I will admit I missed that at first with the 200 hp carbs. But since then I have worked on the right carb without success. I got the boat out but I am still waiting on the head gaskets. I am beginning to gather that all the smart minds on this board still believe it has to be a carb problem. The 225 carbs were used when I got them and while I have went through them twice, and the 200 carbs 3 times, I am used to carbs you can soak in a vat so you all could be right. What makes me think not it both sets of carbs have the same problem with #3 no matter what I swap around. Later this week when I get the heads on and the new power pack on I will spend a lot of time trying to tune the carbs again. I'll let you all know.

I was an OMC trained mechanic way back in 1979. And I always had old cross flow motors since then. This is my first real experience with loop charged (except for the old 75 hp stinger motors) and I am finding there is a lot of difference in how things are done. Yes I know, I am WAY behind the times, and even the motor I am working on is an antique, but I am getting old, what can I say. The boat the motor is on was bought by my Dad when I was 14. That was 43 years ago! It is an old Ouachita that I have also rebuilt twice.

 

[bgrimes422]

I put the head gaskets on and warmed the engine up yesterday on muffs, then re-torqued, put everything together and put it in the water. This morning it wasn't tuning out well adjusting the carbs so I ran a spark check, and guess what. Number 3 isn't firing. I did put the new power pack on yesterday and I re-checked all the connections this morning. Still no spark on #3. So I guess I will put the old timing base on this morning. It checked good with the last power pack. As frustrating as this is I think it might be leading me somewhere.

 

[dingbat]

You're committing the mortal sin of repair....blindly throwing parts at something without first identifying the problem.
As your finding out, short cuts (not thoroughly bench testing individual components) typically end up costing you time and or money.

 

[bgrimes422]

Guilty, and know better. But I don't have all the tools to fully check out electrical components. In some cases, parts swapping is all I can do.

 

[cfauvel]

I put the head gaskets on and warmed the engine up yesterday on muffs, then re-torqued, put everything together and put it in the water. This morning it wasn't tuning out well adjusting the carbs so I ran a spark check, and guess what. Number 3 isn't firing. I did put the new power pack on yesterday and I re-checked all the connections this morning. Still no spark on #3. So I guess I will put the old timing base on this morning. It checked good with the last power pack. As frustrating as this is I think it might be leading me somewhere.

wait what about moving the coil to see if it moved?