Johnson 115 bogs and dies coming off idle

[Davidandkerrie69]

I have a December 2000 built 115Hp V4 60 degree Johnson which starts, idles and runs great at full throttle but bogs and dies when coming off idle. To transition from idle to full throttle, I have to push in the choke primer on the key. The engine will then suddenly pick up, throttle up to full speed and run fine.<br /><br />The engine only has 40 hours on it. I've replaced the fuel line, primer bulb, checked the water sep filter. I've taken the boat to a dealer who said the mixture was way off and he adjusted the off-idle mixture screws. The engine ran a little better - I could slowly nudge the throttle up to full speed without dying. Took it back to the dealer who said it needed another 1/4 turn which he did. Engine started to idle rough and smelt of running rich.<br /><br />For a brand new motor, I'm dissapointed to have problems so early its life. I've read in other posts that probs have been found in late model engines as OMC was going bust so quality was poor. Could there be junk in a carb/s causing the prob?<br /><br />Any assistance greatly appreciated. This is very frustrating as the boat is useless for skiing the way it's running. <br /><br />David

 

[sloopy]

Re: Johnson 115 bogs and dies coming off idle

no its not the engines fualt its the person who put it together.. on this engine is the choke a primer choke or a get out air choke.. and is the timing checked? sounds like the carbs also need to be rebuilt.

 

[Joe Reeves]

Re: Johnson 115 bogs and dies coming off idle

David..... Assuming the engine has no other mechanical problems (compression, ignition), the problem you explained is usually due to one of two causes (or both). Either the timer base is sticking causing the engine to run in a retarded timing situation momentarily, or the carburetors are fouled. In either case, adjusting the carbs is a waste of time.

 

[Brew]

Re: Johnson 115 bogs and dies coming off idle

David,<br /><br />I'm with Joe on this one. My '86 evinrude was experiencing the same problems this past summer. Got the problem 90% fixed by giving the carbs a very thorough cleaning (A small piece of debris was partially clogging one of my high speed jets).<br /><br />I'm still experiencing the odd hesitation or stall and Joe's suggestion re the sticking timer base makes a lot of sense.<br /><br />Joe, how would you resolve the sticking timer base issue? Is it just a matter of applying some lube somewhere?<br /><br />Cheers,

 

[ob]

Re: Johnson 115 bogs and dies coming off idle

David, Also check the adjustment of cam roller on carb linkage.This dictates at what point the carb flaps begin to open in relation to throttle position and timing.Very critical,particularly in throttling out of hole from forward idle.

 

[Walker]

Re: Johnson 115 bogs and dies coming off idle

Brew, to do it right you need to remove the flywheel and the stator. Then remove the retaining clips on the timer base and remove the base and the teflon bushing. Clean everything up real good and re-install coating allmoving surfaces with a good grade waterproof grease of telfon lube. I personally prefer Lubriplate.

 

[Beaux]

Re: Johnson 115 bogs and dies coming off idle

Ob's suggestion concerning cam roller is a good point.. it fixed my problem with my O/b stumble. Although, I would go through entire sync and link of carbs to ensure they are correctly adjusted which includes timing check. Good Luck

 

[sloopy]

Re: Johnson 115 bogs and dies coming off idle

so its agread it has to be carbs? it has to BE This is a textbook example of what bad carbs do.

 

[Walker]

Re: Johnson 115 bogs and dies coming off idle

I think you got it Sloopy. But there's always that 1% that's something else.

 

[Davidandkerrie69]

Re: Johnson 115 bogs and dies coming off idle

Thanks everyone for your responses. The choke is a solenoid enricher. Push the keybutton and it opens a solenoid which allows fuel into the intake manifold. Whilst bogging (if it doesn't stall), if I hold the key in, the engine recovers and roars into life upto full throttle no probs. Some how it looks like its not getting enough fuel when coming off the idle going into RPM's. <br /><br />I haven't checked the timing,compression,plugs Would gunk in only one of the carbs result in this symptom or would it require all four to be affected to show the prob? <br /><br />One of the forum messages I read suggested a piece of gasket / dirt was caught in the idle/off-idle passage unit which caused a simiar prob.<br /><br />I dropped the boat off this morning at the boat shop. The mechanic will take it out on the water today. He is sure it's a mixture problem. Will know this afternoon.<br /><br />I'll keep you posted on the outcome.

 

[Davidandkerrie69]

Re: Johnson 115 bogs and dies coming off idle

The workshop confirmed it's not a mixture setting - they're spot-on. <br />Something wrong with the carbies which are now coming off for inspection. <br /><br />David

 

[Davidandkerrie69]

Re: Johnson 115 bogs and dies coming off idle

The carbs have been pulled apart and found to be contaminated with varnish and gum. Looks like it is a case of using cheap fuel from 'independent' service station and sitting idle over winter resulting in clogging of the carbs, loss of octane level in the fuel. Mechanic said to stick to brand name service stations and pay a few cents more. This is going to put a big dent in the wallet!

 

[Joe Reeves]

Re: Johnson 115 bogs and dies coming off idle

David..... Regardless of where you purchase the fuel, when a engine sits for any great length of time, the carburetors are very likely to foul and gum up. Even treating the fuel and winterizing the engine is no guarantee that the carburetors won't foul.

 

[Davidandkerrie69]

Re: Johnson 115 bogs and dies coming off idle

Thanks for the feedback Joe. In the off season, I take the boat out every couple of weeks and give it a run and have never had problems like this with the old Merc engine. Last season I could'nt do this with the new Johnson as I had the engine off for 6mths whilst I rebuilt the transom.<br /><br />The workshop has cleaned out the carbs and reassembled everything. I gave the shop a call this afternoon and they have run the boat on the water and said it nows runs like a rocket.<br /><br />I had a chance to look at the carbs whilst they were all disassembled. They really don't look all that complicated. There was plenty of gunk coming off the jets which were sitting in carb cleaner. The bowls had varnish coating them, and the pick-up tubes were dirty, gummed. I did notice in one of the fine pick-up tubes that protude into the float bowl a small piece of gunk lodged in one of the tubes. Maybe this was the cause of the problem? Would one carb playing up cause this problem?<br /><br />The shop drained what fuel was left in the tank, although I filled the tank 3/4 full with fresh fuel a couple of days ago. The mechanic said even though fresh fuel is added, the stale fuel does not get diluted. If you have stale fuel, drain the lot and flush the lines before adding fresh.<br /><br />Last thing now is to pick up the boat and pay the bill. Can't wait for that!!!!<br /><br />Thanks everyone for contributing. I hope this is of interest to others in the future.<br /><br />David

 

[Brew]

Re: Johnson 115 bogs and dies coming off idle

David,<br /><br />Glad it sounds like things worked out. In answer to your question re: "could one carb have caused the problem?"....Yes. Basically, if a carb is clogged, the cylinder it is feeding "dies". Losing a cylinder is definitely not helpful to performance.<br /><br />From you description of the carbs (varnish everywhere, etc.) it sounds like more than one of the carbs could have been fully or paritially clogged, causing problems in more than one cylinder.<br /><br />Happy boating!<br /><br />Brew