Carb jet confusion - 1978 200HP Evinrude

[nphilbro]

Model E200849R

My motor was acting up a bit (rough idle and noticeable hesitation at transition point of about 2000ish - 3000ish rpms) so I decided to do a simple carb cleaning.

I pulled the plugs on the 2 jets located on each side of the carb (12 total) and fished bare 24ga copper wire through the small (top) ones and the same copper wire with the jacket through the bottom ones and sprayed the mouth and jet ports with carb cleaner.

I also did a Joe Reeves style link and sync. After all this the idle on the muffs went from a bit rough to quite smooth. Even completely sealed up this motor is too loud to run long enough in the driveway to warm up so I could only let it idle for 15-30 seconds at a time 2-3 times over 20 minutes without getting another love letter from the HOA so I'm not sure what the final outcome will actually be but it was noticeably better. BTW, I'm basing my comparison on a very rough idle on the muffs last night.

A couple questions:
Are the top jets on each side of the outside of the carb air mix jets?
Are the bottom jets on each side of the outside of the carb the idle jets?
Where is the high speed jet located?

I've read in other posts that on some of these 200's they increase the jet size by 2 to compensate for ethanol. ALL gas in my part of Washington is "up to" 10% ethanol but I'm not sure what re-jetting would actually do other than possibly make it run a bit cooler. It seemed to be running pretty well my first time out before I switched to a new tank that had bad fuel (that I just bought) and both this motor and my kicker got plugged and died. The jets I pulled from the top carb (prt/std) and middle (stb) are all #31 which indicates it's at least the original jet/size based on what I can read of the stamp on the carb body.

I don't really have the time at the moment to pull all three carbs for full breakdown and rebuild but I'll probably get to it in a few weeks. In the meantime I hope this simple cleaning/timing/throttle link adjustment will get it back to spec. At least now it hits max advance *before* WOT!


Thanks,
NP

 

[mark1961]

Re: Carb jet confusion - 1978 200HP Evinrude

The high speed jets are located in the bottom of the float bowl behind the plug.....

 

[nphilbro]

Re: Carb jet confusion - 1978 200HP Evinrude

Is it #28 on this or are you referring to #33?
#33 and #26 are the ones I cleaned with the wire.

 

[emdsapmgr]

Re: Carb jet confusion - 1978 200HP Evinrude

You cleaned the correct jets. The high speed jet is # 33. Item 26 is the idle jet. Item 5 is the fuel pullover jet. By next year's model (79), the fuel pullover was only found on the 200/235 engines. Item 28 is the inlet needle and seat. The inlet needle and seat get replaced with new- from each carb kit. I'd run premium fuel in that engine. If you want to really clean the carbs, you need to pull them completely apart and clean the carb body passages with some type of gas-cleaning solvent. Gumout is a typical product which will do that. Spraying carb cleaner through the throat of the carb does nothing. A rough idle, or "lean sneeze" is common in engines that need these passages cleaned.

 

[nphilbro]

Re: Carb jet confusion - 1978 200HP Evinrude

Thanks once again, EMD!

I missed the fuel pull-over jet. I've never seen that on any of my other motors. What's the function of that? It looks like it's easy enough to access with the silencer off.

I'm in complete agreement with you about spraying carb cleaner in there. I'm not sure why I use it, maybe just habit, but I mostly do it only in conjunction with a physical cleaning.

What is your definition of "premium" fuel? Our pumps here have 87/89/91 and all have up to 10% ethanol. I always assumed that the ethanol in the blend made it burn a little hotter already and extra octane would only compound that effect, although I'm not having any overheat issues.

Edit: I'm trying to get the pullover jets out and am having a heck of a time. I have a screw driver I use just for removing jets. I shimmed the shaft with wraps of tape so that it would be centered way back there but I can't see it well enough to know if that's the correct tool. Any advice? I'm probably just going to pull the carbs completely off and rebuild them anyway at this point.

 

[emdsapmgr]

Re: Carb jet confusion - 1978 200HP Evinrude

Those pullover jets provide extra fuel at high rpm's. Unique to the high hp engines only in later years. The Bombardier special jet tool is the one to get all their jets out. 317002. I run 91 octane in all my crossflow V6 engines.