1986 Johnson 30hp carburetor / air filter?

[Flugelmeister]

Hi, I have a 1986 30HP Johnson. It runs OK at idle but at high throttle it loses power. If I reduce the air intake on the carbi (by putting 2 fingers over it) it runs great!!!

Do these engines have an air filter? What could be a solution to this problem???

 

[JB]

Re: 1986 Johnson 30hp carburetor / air filter?

Howdy, Flugelmeister.

Welcome to iboats.

You only need an air filter on dusty lakes. Your engine is clearly running lean. Carburetor needs cleaning.

Good luck.

 

[Flugelmeister]

Re: 1986 Johnson 30hp carburetor / air filter?

Thanks for the quick reply - would you recommend a carbi kit or should I try to disassemble, clean & reassemble?

Also have heard of "boiling" the carbi - what steps are recommended?

Cheers!

 

[JB]

Re: 1986 Johnson 30hp carburetor / air filter?

I would get a kit. One can pretty much clean 90% of the suspect passages without a kit if he is very careful not to damage gaskets, etc., but to properly clean out the orifices in the carb throat you have to remove (destructively) the plugs that block access to them.

If you don't have it already, you will also need am OEM Service Manual to do the job correctly. www.outboardbooks.com

Good luck.

 

[Flugelmeister]

Re: 1986 Johnson 30hp carburetor / air filter?

Hi JB, thanks for the link but it's not working for me right now (will try again later). I've bought the "Seloc" PDF manual online covering 71/89 Johnson/Evinrude but the carbies do not match up completely, the closest I've found is the "Type IV" carburetor but again not identical... My outboard is a 1986 30HP Johnson BJ30BACDM (which seems to be pretty similar to a J30RLCDM) so I have been going off that.

Anyway being Easter I thought I would take a crack at the carbie without the kit. I have a few Q's if you don't mind!
1. The carbie is shown assembled here http://www.flickr.com/photos/43434047@N05/5650279865/in/photostream part number on the tag is 396211 MX 06 E L
2. The needle valve is worn unevenly all round (shown here) http://www.flickr.com/photos/43434047@N05/5650280927/in/photostream and i don't think it has a bearing at all!!! (unless it is wafer thin and metal coloured I can't see one in there...)
3. The tube taking the fuel from the float tank is pretty damaged on the tip (maybe from a past pair of pliers..) but that shouldn't have any effect right? http://www.flickr.com/photos/43434047@N05/5650280445/in/photostream
4. The air inlet valve (comes from the choke assembly) at the top of this image appears to be completely blocked... I have blown it out with compressed air with no luck - should I poke it out with a pin or am I likely to damage something (is it a vacuum valve or something?) http://www.flickr.com/photos/43434047@N05/5650846640/in/photostream

Other than this the carbie looks quite clean - next steps I plan to do are to fit a new low speed needle valve & bearing (if I can find them) and poke out the hole in the air inlet valve and whack it back on...

Any suggestions appreciated!

 

[JB]

Re: 1986 Johnson 30hp carburetor / air filter?

Your questions reach far beyond my fragile old memory, Friend. I think you need the kit and the OEM Manual. Were I in your position that is what I would get before doing any more.

 

[F_R]

Re: 1986 Johnson 30hp carburetor / air filter?

I don't have direct experience with that exact model either, but...

#2..The needle is clearly damaged. That would make it difficult to get a good idle mixture adjustment. But you said your motor idles well, so that is not an issue. The parts book for your motor does not show an idle needle bearing. That's strange, but like I said, I don't know that exact model.

#3.. So some clown tried to remove the non-removeable high speed nozzle. Probably will work ok. If not, you need a new carburetor. You DO have the gasket that goes around the nozzle...don't you?

#4..The fitting is the primer fuel. Strange that it would be completely plugged. But once it is running the primer does nothing, so that isn't your problem with high speed operation either.

#5..Your real problem almost certainly is the high speed orifice plug in the bottom of the float bowl. You can almost bet the farm that it is partially clogged/dirty. It must be absolutely, positively, squeeky clean!! Even a trace of any contaminates in there will cause the problem you are describing. Do NOT go probing wires and stuff through it either. It is a precision orifice and oversize/damaged is as bad as dirty.

 

[Flugelmeister]

Re: 1986 Johnson 30hp carburetor / air filter?

Hi F_R, thanks for the tips!

#2. Yes I can get a good idle mixture so I haven't been too concerned. My parts book does show a idle needle bearing, but I don't have one... but as you said I can get a good idle.

#3. Nope... no gasket on the high speed nozzle... just what you see here http://www.flickr.com/photos/43434047@N05/5650280445/in/photostream

#4. At the bottom of my float bowl there is a tube connecting the high speed orifice directly to the primer / choke - not with a "plug" as described in the manual. You can see it here http://www.flickr.com/photos/43434047@N05/5650279865/in/photostream

After taking it out today and making some tweaks, it definitely runs better at higher revs than before, surges... but it still has a problem. I have pretty much ruled out "too little fuel" and assume the problem is "too much air". I have disassembled and reassembled the primer system and all seems OK.

I have one question I can't find - what position should the "flap" inside the carbi barrel be at full throttle, should it be completely open?

At the moment I am considering a "two finger workaround", that is putting a plate on the front of the carbi to reduce the air into it. Won't solve the root cause but may give a better result...

 

[Paramedic83]

Re: 1986 Johnson 30hp carburetor / air filter?

I have the same problem with my 89 30hp johnson. I put my fingers over carb to block air flow it runs better.I have rebuilt the carb new fuel pump, head gasket now i put a new coil pack on it today going to try that out. Let me know if u figure out the problem please i will do the same.

 

[oldslowandugly]

Re: 1986 Johnson 30hp carburetor / air filter?

The high speed orifice (jet) is in the float bowl, behind that nipple with the fuel line from the primer that is in this picture> http://www.flickr.com/photos/4343404...in/photostream. You need a special tool to remove it, or a fat screwdriver that has been ground down to fit the orifice slot. Once removed, check the size. OMC used all kinds for different motors, it may not be correct, or just dirty. As an example, my 80' 35 hp came with a #59 jet and would only tach out to 4500 rpm. By changing to a #61 jet, it woke right up and revs to 5800 rpm now. At WOT, the "flap" should be perfectly horizontal, that is wide open, but no more or you risk jamming it and that is bad. Also, that carb is slightly larger by 1/8th" than earlier models, and takes a fairly big jet. My 85' took a #63.

 

[JB]

Re: 1986 Johnson 30hp carburetor / air filter?

I have the same problem with my 89 30hp johnson. I put my fingers over carb to block air flow it runs better.I have rebuilt the carb new fuel pump, head gasket now i put a new coil pack on it today going to try that out. Let me know if u figure out the problem please i will do the same.

This is what we call a hijack, paramedic. Don't do that. This thread belongs to Flugelmeister. It is rude to redirect our attention away from his trouble to your trouble.

Please start your own, new thread about your problem.

Thanks for your cooperation, and good luck.

 

[Paramedic83]

Re: 1986 Johnson 30hp carburetor / air filter?

Only problem i seen like that sorry im a rookie didnt know the rules.But yeah Flugelmeister i hade a bad wire from my wire rectifer problem solved.

 

[Flugelmeister]

Re: 1986 Johnson 30hp carburetor / air filter?

Hi there! Based on the comments from F_R I had a closer look at the carbi and noticed that there was no gasket on the high speed nozzle! I replaced this but did not get to test it until last weekend (because I overtightened the "nipple" and destroyed it... doh!) This part then needed to be ordered and in the meantime replaced any other old fuel lines etc.

Tested it last weekend - the engine is a completely different beast, runs great at high speed which you can see here http://www.youtube.com/watch?v=2Qmhm2nlIfg

Thanks to the posts in this forum I found the problem, otherwise might have overlooked the gasket (just like the last guy did Cheers!

 

[Paramedic83]

Re: 1986 Johnson 30hp carburetor / air filter?

Fluegel can you somehow send a pic of that gasket you put in and where it went. thanks im still having problems.

 

[Flugelmeister]

Re: 1986 Johnson 30hp carburetor / air filter?

Its part number 7 here http://tinyurl.com/3euua3k

Goes over this http://www.flickr.com/photos/43434047@N05/5650280445/in/photostream

Craig.