Surging at throttle and does not like low throttle

[KCShorty]

I just recently started having a problem with my 1982 25hp tiller Evenrude. It will start when doing the cold start procedure, but dies shortly after pushing the choke in. It will run with the choke pulled. It will also run if I put it into gear with the choke pulled and give it some throttle and then push the choke in, but it starts to surge at throttle once the choke is pushed back in. Also, when the choke is pushed in and I go to slow the motor down while in gear, it stalls. So it does not like low throttle while in gear and no choke. Pumping the fuel bulb does not help. Not sure the last time the carb was rebuilt. I have owned the boat for 1 season and this is the first issue i have had with it. I am thinking carb rebuild time. Any suggestions/confirmations/opinions?

 

[Daviet]

Re: Surging at throttle and does not like low throttle

If the spark and compression are good, it sounds like it is time to overhaul the carb. Make sure you remove the core plug on top of the carb and clean the passages underneith. Make sure that you remove all the orifices and clean them properly.

 

[kenmyfam]

Re: Surging at throttle and does not like low throttle

If you don't know when the carb was re-built last then it is time to re-build it.

 

[KCShorty]

Re: Surging at throttle and does not like low throttle

If the spark and compression are good, it sounds like it is time to overhaul the carb. Make sure you remove the core plug on top of the carb and clean the passages underneith. Make sure that you remove all the orifices and clean them properly.

I know the compression is good as I tested it when I purchased the motor. Have not tested the spark though. I think I am going to rebuild the carb with the Seirra kit I bought and see if that clears up the problem. I will take a look to make sure I can find the core plug and passages you talk about. Does anyone have a photo of these? This is my first carb rebuild. Thanks guys!

Edit: forgot to ask. Once I have the carb all pulled apart, is it better to do a chem-dip cleaning or just use spray carb cleaner and compressed air?

 

[KCShorty]

Re: Surging at throttle and does not like low throttle

ok, so i think i found the core plugs ou were talking about. The are the curved disk looking things in the carb kit. They look like the are removed from the outside looking at the diagram attached below. part #4 & #5?

http://www.boats.net/parts/search/BRP/JOHNSON/1982/J25RLCNB 1982/CARBURETOR/parts.html

so how do i remove these and install the new ones? thinking an awl to removed them.....not sure the best tool to use on the install though?

OnceI have the carb all pulled apart, is it better to do a chem-dip cleaning or just use spray carb cleaner and compressed air?

 

[relocyo]

Re: Surging at throttle and does not like low throttle

Although im no expert ive rebuilt my carbs twice with the help of this forum, suggest def. An overnight min sprits bath, just be sure no plastic goes in the bath, and I removed my "core plugs" (although I recall them being called something else) with an old very fine tipped phillips screwdriver and a hammer, bang down, pry out, repeat... Hope it helps! Or im sure a sharp awl would work...

 

[relocyo]

Re: Surging at throttle and does not like low throttle

Forgot to mention, carb cleaner and compressed air after the min spirits bath, and use a small piece of wire to clean out the orifices, while Im not sure if you've high speed and low speed jets using wire to clean all the orifices is standard operating procedure

 

[Monte1961]

Re: Surging at throttle and does not like low throttle

Don't drill in to the carb itself. The other word your looking for is a welch plug. 1/8 to 3/16" drill bit and a pick should do the job. And I wouldn't bang on any carb unless you want to destroyed!

 

[relocyo]

Re: Surging at throttle and does not like low throttle

Ok dont "bang" on it geeeeez....

 

[KCShorty]

Re: Surging at throttle and does not like low throttle

Thanks guys, very helpful. One last question(hopefully). How do the new core/welch plugs go in? The ones that are on the carb now are flat. The ones in the kit are curved/domed, so not sure which side up they go. So domed or dimpled side up? And whats the best tool to tap them in with?

 

[levi_tsk]

Re: Surging at throttle and does not like low throttle

curved side up tap on the center until it flattens out - i use a 3/8" drive extension and a small hammer - the extension has a rounded end that makes a nice dent or you can use a largish pin punch dont get carried away - if you go too far itll curve the other way and thats BAD

i like to sit down in a chair and put it in my lap otherwise you can crack the casting if you set it on a table

 

[Monte1961]

Re: Surging at throttle and does not like low throttle

Dont know if this the correct way, but this is how I do it with good success! Install dome side up. Take a brass drift about half the size if core/welch plug and lightly tap with mallet just enough to make it expand. You can also afterwards, put some fingernail polish or white OMC sealant around the edges. Good luck and let us know how you make out!

 

[KCShorty]

Re: Surging at throttle and does not like low throttle

Wow...you guys are so helpful and fast! I got the carb all pulled apart and ready to dunk in the cleaner. couple questions. There are two holes on either side of the nozzle, one is open and the other has a plug in it. The one that is plugged looks to be another core/welch plug on the carb body( under where the bowl sits). Is that a plug and does it need to come out?

Also, should the nozzle be removed for cleaning? I am planning on leaving the butterfly valves in while cleaning, is that ok?

Lastly, there apears to be a metal tube down the middle of the nozzle. So its a tub within a tube. The inner tube is pushed to one side and is touching the inside wall of large tube(nozzle?). Is this the correct setup or is it fouled?

Sorry for all the questions, but this is my first time and I want to get her back on the water for a weekend of fishing!

 

[relocyo]

Re: Surging at throttle and does not like low throttle

Eh, pics would help... Dont gave a carb. Sittin in front of me...

 

[levi_tsk]

Re: Surging at throttle and does not like low throttle

yeah pics help ALOT

 

[Monte1961]

Re: Surging at throttle and does not like low throttle

Wow...you guys are so helpful and fast! I got the carb all pulled apart and ready to dunk in the cleaner. couple questions. There are two holes on either side of the nozzle, one is open and the other has a plug in it. The one that is plugged looks to be another core/welch plug on the carb body( under where the bowl sits). Is that a plug and does it need to come out?

Also, should the nozzle be removed for cleaning? I am planning on leaving the butterfly valves in while cleaning, is that ok?

Lastly, there apears to be a metal tube down the middle of the nozzle. So its a tub within a tube. The inner tube is pushed to one side and is touching the inside wall of large tube(nozzle?). Is this the correct setup or is it fouled?

Sorry for all the questions, but this is my first time and I want to get her back on the water for a weekend of fishing!

Ok to remove high speed jet. Little tube inside is suppose to be there! DON"T TRY TO STRAIGHTEN IT!!!!! thats the way its supposed to be!

 

[KCShorty]

Re: Surging at throttle and does not like low throttle

I dont have the ability to put pics up at this time, which sucks. I think I have figured it all out though. That was another welch/core plug under the carb body, so I removed it. I soaked the carb body with the butterflys still attached. And I am leaving the nozzle as it is and not messing with it. I will report back once I have her all back toghter and running. Thanks again!

 

[Monte1961]

Re: Surging at throttle and does not like low throttle

Always a good thing to ask if you dont know or unsure. Post back and let know if you need anymore help!

 

[KCShorty]

Re: Surging at throttle and does not like low throttle

Ok guys. Got her all back together. She seems to run real well in the test tank. Hope to take her out next weekend and see how she runs on the lake. Wanted to say thank you again. Would not have had the confidence to do the job without your help.

Quick question. I have read on here that a "link and sink" are suggested to help the motor run 100%. Is this something I should try to do on my motor as I'm not sure the last time it was done? Or if it ain't broke, don?t fix it approach is best. If I should do it, is there a how to or thread that can help?

 

[levi_tsk]

Re: Surging at throttle and does not like low throttle

well youve only got one carb so in this case you want to make sure that its opening all the way at full throttle and that your wide open throttle timing is correct refer to joe reeves timing a johnson or evinrude outboard its in the "top secret files " at the top of this forums main page