My 1994 johnson 225 back fires/ sneezes at idle

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

So, you got it apart, and are waiting on parts? Is that the status right now? If so, here are some tips in re-assembly: 1. Reed block gasket is a long rectangle. The "long side" of that gasket tends to squish out , or bulge out, after you install the 4 screws that attach the reed block to the intake. It doesn't squish at that moment. It waits until you have it all back together, then it squishes out:joyous:. I always use an adhesive to glue that gasket on better before assembly. I use 3M yellow weatherstrip adhesive very lightly, wiping up any excess if it oozes out. The symptoms if it squishes are this: Massive gas raining out the front of the carb when running. Just remember which reed gasket you replaced, and if that carb is raining gas out, then reed block gasket has squished out. 2. On that intake....I forget which screw it is.....but there is ONE screw that has interference with the casting of the intake, that you cannot get a socket on. You have to assemble that screw first, before you , say, put the upper intake on (or lower) I forget which....but there is one screw that is a PITA. It is lower center either on the upper intake or on the lower intake. If you don't do it first, you will have to remove everything you just assembled just to get to it to put it on and torque properly. PITA. 3. You may not think about this, but once you remove and then re-assemble the throttle bodies, you MUST re-sync the throttle butterflies. Just the simple R and R of those bodies, can, and usually does, throw the butterflies out of sync, most often a butterfly will be slightly open on the bottom two cyls. Sync the throttle plates/butterflies with the black carb bodies OFF. You can see the whole thing way better. All butterflies must be completely closed, and operate in exact sync with each other. Perfection is critical here for proper idle.

Yep whole front of the motor is disassembled down to the block ... waiting on a reed block gasket, new manifold, carb, and throttle body gaskets are in and I picked those up yesterday. Funny how a $3
part can hold you up ... :/
GREAT INFO Daselbee I appreciate the help !!! I think i'm gonna have the local shop do the link and sync I feel like I owe them for all the help they've been and they said it'd be 85 bux might be $$ well spent. That MAY have been the problem in the first place because the previous owner did take the carbs off and may have taken the throttle bodies off as well.

Yea I know EXACTLY which screw you're talking about because I ALMOST couldn't get it off it's on the bottom middle of the upper intake and yea TOTAL PITA! I know this because I only REALLY wanted to take the upper manifold off and leave the lower intact HOWEVER that particular bolt decided that it wasn't gonna go down like that .... I always try to put all the screws in stuff first running them down til they just touch and then run my torque pattern but i'll keep all that in mind when I'm reassembling tomorrow top manifold first ... the reverse of how it came off.

As far as the reed block goes mine only has two hex head screws holding each one on and I'll use some weather strip adhesive upon reassembly.
Where can I get that stuff at? Is that the stuff they call elephant snot??

 

[daselbee]

Re: My 1994 johnson 225 back fires/ sneezes at idle

You don't have to pay for the link and sync. I'll help you via phone on that if you PM me with a number. Re the screw....yep that's the one. Now, the glue....that is a toughie. Here is why. when you re-assemble and place the gaskets, the assemblies are supposedly clean of old gasket material, oil, etc., right? So the gaskets come with an adhesive on one side, and you peel off a wax paper covering, and stick the gasket on. That glue doesn't hold. BUT it holds well enough to run for a while, and then the GASOLINE running thru there works on it, and they walk out of their proper location. So, here is the problem: you have to use a glue that is fuel resistant. I don't think the 3M weatherstrip adhesive is fuel resistant, but I use it very sparingly, and I mean VERY sparingly, and it has seemed to hold. So the 3M weatherstrip adhesive is available at almost any auto parts store if you want to try that. Maybe some of the seasoned looper experts can recommend a better product. And, no, it is not the "gorilla snot" product you refer to. That is Permatex Aviation Formagasket in a white plastic bottle. Links to both are shown here: Gasket Sealants : Permatex? Aviation Form-A-Gasket? No. 3 Sealant Liquid and On-line Product Catalog:?3M

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Something is not right. Go to shop.evinrude.com, look for your motor, look at the carb pages, and compare orifice sizes. Items #3 and #5 on the drawing. Looks like a carb tinkerer has been at work.

Are the orifice #'s the same as the number printed on the front of the orifice mine clearly say 36 and 46 on the front...? Is it possible they were changed when the rebuild was done due to an overbore on all the cylinders?? I'm gonna check and make sure that they aren't orifices from a 250 or a 200 a bigger hole than stock in the orifice would cause it to run leaner at idle correct?

I've seen some automotive jets that have the size printed on the front of them and the catalog lists the mas a different number could this be the case here?

 

[daselbee]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Yes. The number stamped is the same as the number referred to on the parts pages. See what I mean about something being way off....not right....Who knows why they are not right. Guys mess around with these orifices all the time. Just about every looper carb set I have purchased (EBay) has the wrong jets in them. You have a real task on your hands now, just determining which year carbs those are, because even they may have been swapped in at some time in the past. Keep in mind that the carb bodies and the throttle plates make up the complete carb assembly. They go together. It is always a toss up as to whether the black bodies have been replaced onto the wrong throttle bodies. Try to locate the carb part number which is usually on a white sticker on the side plates of each carb. There may be one there that is still readable. Part numbers that you find in the plastic bodies are casting numbers, and will do no good. Dang, I wish they would publish some sort of casting number reference document.

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

You don't have to pay for the link and sync. I'll help you via phone on that if you PM me with a number. Re the screw....yep that's the one. Now, the glue....that is a toughie. Here is why. when you re-assemble and place the gaskets, the assemblies are supposedly clean of old gasket material, oil, etc., right? So the gaskets come with an adhesive on one side, and you peel off a wax paper covering, and stick the gasket on. That glue doesn't hold. BUT it holds well enough to run for a while, and then the GASOLINE running thru there works on it, and they walk out of their proper location. So, here is the problem: you have to use a glue that is fuel resistant. I don't think the 3M weatherstrip adhesive is fuel resistant, but I use it very sparingly, and I mean VERY sparingly, and it has seemed to hold. So the 3M weatherstrip adhesive is available at almost any auto parts store if you want to try that. Maybe some of the seasoned looper experts can recommend a better product. And, no, it is not the "gorilla snot" product you refer to. That is Permatex Aviation Formagasket in a white plastic bottle. Links to both are shown here: Gasket Sealants : Permatex? Aviation Form-A-Gasket? No. 3 Sealant Liquid and On-line Product Catalog:*3M

Ok good info NAPA here in town carries that permatex stuff and I've seen the 3M weatherstrip adhesive at ace and Advance auto parts and possibly NAPA too I'm willing to wait if it means a better solution to the reed assembly god knows I don't wanna have to do this again if I don't have to... anyone want to chime in in agreement or with a better sealer?

 

[Bosunsmate]

Re: My 1994 johnson 225 back fires/ sneezes at idle

That permatex aviation stuff ive put in all sorts of places on outboards ive worked on and its never brought me any problems

 

[daselbee]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Can't use Permatex here. That stuff actually never dries, and will "lubricate" the gasket and cause it to squirm out of place quicker. You cannot use RTV either, as RTV is not at all fuel safe. There are two other products that might work that I know of. Both are old school stuff, and very hard to find, and may not work even if you do find it. One is Indian Head Gasket Shellac and the other is Gasoila. I have bought Gasoila before, but it is so old on the shelf (never sells) that it was literally dried up. Tractor Supply has it in some stores, and the larger industrial supply houses carry it, but that is where I got it all dried up. I have never used Indian Head Shellac. You may question all this extra glue requirement that I am throwing in here.....but I know the troubles I have had with the long side of that gasket walking and squirming out of place, and it is just too much work to dis-assemble to fix something so ridiculous as a gasket that has moved......I was advised by a well known engine rebuilder and manufacturer of fiberglass reeds (who could that be?) to use the 3M, and it has worked. Assemble and let dry (cure) before starting.

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

ok cool how long 24- 48 hours to be safe or? boyesen knows their stuff ill go with your suggestion Daselbee thanks a ton gasket came in this morning and I should have it back together this afternoon what would you put on the intake bolts that need sealer ? more 3m adhesive or?

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

I've used the Indian head shellac in automotive applications where its BURRIED in fuel and it works GREAT as long as you let it cure fully before you try to utilize the part and I'd imagine that MIGHT work here but like you were saying it sits on the shelf so long a new bottle may be dried up so check it before you purchase it most NAPAs have it for anyone's reference that need it.

and having experienced the same problem before in a car I FULLY appreciate your doting of sealers because I'VE BEEN THERE BEFORE

 

[daselbee]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Use the Permatex gorilla snot on the intake bolts that need sealer. Oh, and not Boyesen.....someone else... (CC).

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Ok so I got the Reed block back on with the weather strip adhesive the manifolds back on and so are the butterflies but I can't get the top two butterflies (#1 & #2 cylinder) to close fully what do I need to do now? The bottom four throttle plates are closed but the top two are open just a hair with the throttle linkage hard against the stop...

 

[daselbee]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Well, you are going to have to put on your mechanical thinking cap to figure this one out. As you know, the each side upper throttle bodies are one assembly containing two butterflies each. They are made together, and as such, should operate together. After all, the butterflies are on the same shaft.... If it were me, I would remove the one of the upper assemblies and inspect it closely to see why they aren't in sync. The only thing I can think of that would cause what you are saying is that a butterfly is bent. Be sure about what you are doing....the single lower throttle body can prop open the two uppers because of a mis-adjusted connector link on the shaft. You sure that is NOT the case?

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Yes I'm sure, I wish I WAS wrong though and yea the middle ones are shut and the bottom two are shut top two are open just a hair. When I tap on them they sound hollow the others don't and I can see a small gap less than a 32nd" wide between the bore and the butterfly on the top two.
I'm thinking about that $85 link n sync again and its sounding pretty good ... but I'm gonna check the middle and top butterflies for straightness first though because maybe they got bent or out of wack from each other somehow by the PO. I think that's whats going on so im gonna check it with a small straightedge I have while holding the throttle all the way open.
Thanks again daselbee
My manual hasn't shown up yet anyone know how many degrees advanced on this motor is supposed to be at WOT? I'm not gonna check it till later on to be safe on the reed block but I'd like to have it handy for tomorrow

 

[daselbee]

Re: My 1994 johnson 225 back fires/ sneezes at idle

18* ATDC. You better call me, PM sent. EDIT: WHOOOOO....GEEEZ...not ATDC BTDC.....sorry. It is 18* BTDC. urfff....:facepalm:

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

I called ya you weren't home lol that 18* is with or with out the 4* subtraction?
Also I guess I was delusional or something last night because they are all six shut now I just might not have been holding my mouth right or something plus I couldn't see that great last night cause it was getting a little dark so the linkage is set properly now I gotta check the timing and do Boobie's check on the powerpack

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Are the orifice #'s the same as the number printed on the front of the orifice mine clearly say 36 and 46 on the front...? Is it possible they were changed when the rebuild was done due to an overbore on all the cylinders?? I'm gonna check and make sure that they aren't orifices from a 250 or a 200 a bigger hole than stock in the orifice would cause it to run leaner at idle correct?

I've seen some automotive jets that have the size printed on the front of them and the catalog lists the mas a different number could this be the case here?

well I was wrong ... the jets HAVE been changed... What do I do now????

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

Yes. The number stamped is the same as the number referred to on the parts pages. See what I mean about something being way off....not right....Who knows why they are not right. Guys mess around with these orifices all the time. Just about every looper carb set I have purchased (EBay) has the wrong jets in them. You have a real task on your hands now, just determining which year carbs those are, because even they may have been swapped in at some time in the past. Keep in mind that the carb bodies and the throttle plates make up the complete carb assembly. They go together. It is always a toss up as to whether the black bodies have been replaced onto the wrong throttle bodies. Try to locate the carb part number which is usually on a white sticker on the side plates of each carb. There may be one there that is still readable. Part numbers that you find in the plastic bodies are casting numbers, and will do no good. Dang, I wish they would publish some sort of casting number reference document.

just saw this post ... $H!T !!!!!!! this sux... just when I thought things were going well....... checked and the part number white sticker is missing on all of them ... looks like someone put 250hp orifaces in there .... great so now it's gonna be lean at idle cause they are bigger what now bud????!???
I see now why manufacturers are getting worse and worse about having no user serviceable parts in stuff now...

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

just saw this post ... $H!T !!!!!!! this sux... just when I thought things were going well....... checked and the part number white sticker is missing on all of them ... looks like someone put 250hp orifaces in there .... great so now it's gonna be lean at idle cause they are bigger what now bud????!???
I see now why manufacturers are getting worse and worse about having no user serviceable parts in stuff now...

EDIT:
Part number WAS present on the carb they are all #433562 and #433563 also looked and the 1990 model 225 had the #46 and #36 air bleeds in it looks like judging from all that they came off a 1990 225 does this mean I'm safe or??

 

[levi_tsk]

Re: My 1994 johnson 225 back fires/ sneezes at idle

ok now ive got fuel leaking out between the carb bowl and the carb body all screws are tight what now?? replace the gaskets or just reman the whole bunch.... I know it won't run right like this .... ???