Carb issues Evinrude 15 HP

[Dizz]

Not sure how old motors must be to ask here?
Im new here had tough time to register,91 15HP Ive had since 99.Always been strong motor.!00PSI compression both cylinders.Not had it started in 4 years but I always let it run dry.Noticed I had rough idle this time.Took carb apart and noticed the nylon plastic piece center of float had a crack in it.Its called nozzle well and a discontinued part.Same for 8HP as far as I can see,but since they don`t come with high speed jet I just put my jet in it.Put kit in as well and cleaned it.Still had rough idle but worst was stumbling at middle rqnge,strong wide open.Tokk it apart again but this time bought gallon of carb clean and soaked it 18 hrs.Tried again and middle range improved,but still bit rough at idle.I adjust low speed jet lean till it needs choke to start,then richen it up till it starts easily.Any ideas on other areas I should look?Amy ideas of issues caused my that cracked nozzle well as I can find no imformation antwhere as well as nothing on LeRoys ramblings on this.I found no welsch or lead plugs to remove to get to any hidden passages to clean on the carb.I also just bought a 90 model rope start with similar issues.I do get some of the sludge dripping from motor indicating a rich motor that this motot never used to do.Many Thanks!

[crosbyman]

part me be available …seach ebay google etc… try Tim’s OUtboard and others did you try iboats ??

Joining AOMCI has priviledges 🙂

[fleetwin]

OK, so the white plastic fuel pick up was “cracked”…Did you replace it? I’m thinking there was not much of an issue if the engine ran OK at high speeds. How about the little hose that runs from the white pick up to the tube on the carb body? These were notoriously flimsy, today’s gas usually caused them to disintegrate. The later, improved hoses were brown in color, what color is your hose? Not only did the original hoses disintegrate, but the debris left behind oftentimes plugged up the tube and idle passages.
Does the engine respond appropriately when you mess with the idle fuel needle? Can you make it too lean or too rich? If so, it would seem as though the carb is performing adequately. Are you sure the carb butterfly is synced properly? It should be completely closed at dead idle. Not likely this adjustment would have changed unless you messed with the little allen head screw on the carb roller linkage.
Are you sure you don’t have a spark issue, have you replaced the plugs? Is the engine coming up to temperature at idle? It won’t idle well if running cold.
Just want to be sure I have it right, the engine has never run right since you commissioned it this time after sitting for a few years, correct?

[Dizz]

Yes I replaced the plastic nozzle well with a new one for 6-8HP as these are available and look identical to me,you have to take high speed jet from the old one and screw it in new as they dont come with one,,different part # but Im sure it`s the same.My little original hose off it was thin wall black and looked good.The OMC repair kit had a new one,black,very heavy wall hose and with tiny hole was bugger to get on.

I did mess with the little allen screw because I somehow broke then cam follower and had to order a new one.I did the link&synch by making sure the throttle didn`t open and till the mark on plastic thingie was lined up.To do this I had to adjust the ball on the throttle cable and move it quite a bit
.New Autolite plugs.
I do hear some difference when I adjust slow speed jet,when I lean it up it starts to sound better,but then it wants to die and won`t restart without choke,so I richen it up till it starts easily warm or cold.
I think your on to something with the engine not getting to operating temp,as the water out of the pee hole never gets over luke warm wide open.Could I have stuck thermostat?Is this common?
Again it does better in mid range since adjusted the synch and soaked carb and runs like scalded dog moving my 1543 jon 21mph with 2 people.
Again thanks!

[fleetwin]

OK, well the can’t judge engine temp by telltale temp because the telltale is at the beginning of the cooling flow. Telltale temp should never got hot, it will usually be cool or warm.
It is interesting that there are a few different style high speed nozzles, one for a 6hp, the other for the 8hp. Your 15hp takes the 396605, which is unavailable, which nozzle did you use?
It sounds like you have the sync set up OK, but are you sure the throttle butterfly is closing fully at idle?
It is not uncommon to have to restart a warm engine with the choke, especially in the hot weather, mostly due to fuel volatility and heat soak issues. So, don’t leave the adjustment needle excessively rich just so it will start without the choke.
Engine temp is measured on top of the cylinder head, we would like to see about 140 degrees at low speeds, it will cool down a bit when run at higher speeds. The thermostat sits on a rubber seat with a spring holding it in place, so high water pressure can push it off its seat at higher speeds cooling the engine down a bit. So, it is not uncommon to find debris between the thermostat and seat keeping the engine from warming up at low speeds.
Sounds like you left the original idle hose in place which isn’t a good idea…Todays fuels rot these hoses pretty quickly creating debris which can plug up the carb.
Try to post a video of the engine running poorly, there are many possible causes other than just carb issues…

[Dizz]

I used new nozzle 0397189 for 6-8HP that is available and $28+.I did find correct new part be he wanted $80 for it.They do NOT come with high speed jet anyway,I just threaded my old one in it.It is identical plastic part as far as I can tell and have been told either will work.I did not use old hose although it looked fine.I used new heavy wall black hose from the current OMC kit not Sierra but was so much heavier rubber that old one or it or old hose just shrunk.The center hole in new hose was tiny and difficult to slide on.
Although I feel I did proper Lynch/Synch when you idle my motor it has to open past fully closed butterfly to run.
I will put motor in barrel and use my thermometer to try to see what it goes to.Thought about doing like 70 Impala and putting it in pot water with thermometer to determine when it opens,also want to look for debris that could do as you say and hold it open.Due to pictures showing it is black plastic and not brass leary about putting it in a cooking pot.
Not only is it need choke on to start if I lean it up where it idles better if idled for a short while it will die so I turned just enough richer to run extended idling.
I am not savvy enough on computer to add a video here.
Thanks Again!!

[Dizz]

Think engine temp the issue.After 10 minutes at trolling speed in tank never got over 90F top of head and 102 on bottom.Took thermostat out and lots of flakes&junk.Couldnt really clean the plastic housing just flushed it out but I did take steel wool and clean the housing and rugger seat that was so nasty.Now gets hot enough you cant keep your hand on upper head for just second.Water out of hole is warmer as well.I could tell it was running smoother and not nearly as much smoke.Won`t know for sure till I get it on the water.

[fleetwin]

Sounds good, these engines will definitely idle much better if they warm up quite a bit. Don’t worry about melting the plastic heating the thermostat in boiling water, it will stand up OK.

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