79 evinrude carb problem(Video)

[Kajun37]

I've been trying to get my 79 rude 15hp model 15904E running since i was able to get it unfrozen.........i've taken apart the fuel pump and cleaned it well...put a new carb repair kit on it..new foat and bowl...it supplys fuel to the carb like it supposed too..but somewhere in the carb i must have some blockage, i'm not getting fuel into the throat of the carb..the bowl will fill up but i've noticed it wont come up into the area of the needle and big plug ....i've cleaned the carbs a couple of times...blowing out all passageways jets that i can find... took out both plugs..

with the carb on it wont start...i took off carb and sprayed fuel/oil mix directly into intake/reed area and she fired up first crank..i shut it down real quick ....definetly a fuel delivery problem.

took apart again and cleaned it again..took out plugs and blew those out..only thing i havent taken out is those lil leadshot plugs.....i would do it but dont know how and wouldnt know how to get them back in ...

any tips or suggestions would be appreciated!


here is a video i made today on the problem.....

http://www.youtube.com/watch?v=V7B1JuR6e0E

 

[Xcusme]

Re: 79 evinrude carb problem(Video)

Under the small metal disk, on the carb top, are the idle ports. Make sure the very small holes are not clogged. Use a flashlight from inside the carb throat to make sure they open. The slow speed idle needle supplies fuel to the cup underneath the metal disc, which is then metered through those small holes into the carb throat. Place the replacement disc crown side up and flatten with a flat punch. I use a very small amount of gasket sealer around the outside of the disc edge to insure a seal. Those lead shot seals are simply that, lead shot to seal the cross drilling of the carb body and it shouldn't be necessary to remove. The float drop looks good, as does the replacement carb bowl (new I assume).

 

[Kajun37]

Re: 79 evinrude carb problem(Video)

i'm assuming the small metal disk you talking about is what i call the the large plug that is on top?? it has 3 small holes at the bottom that go into the throat of the carb...and one other that comes from the low speed needle chamber....all 4 of them are clean and not clogged..i have blown carb cleaner through every hole i could find....i'm thinking whatever is supplying the low speed needle chamber and that space under the plug with fuel is clogged??

shouldnt the the copper tube that is in the middle of the carb and goes down into the bowl bring excess fuel into the carb throat when the bowl is full??..well it doesnt...and it is totally clean and not clogged either..

what do ya'll use to soak carbs in? i have only sprayed this one clean...but i have sprayed the heck out of it...used a whole can of carb cleaner plus some out of another can on it.....

here is a pic of the space under the top plug....

here is the copper tube that comes from the bowl into the throat of carb..

 

[klicknative]

Re: 79 evinrude carb problem(Video)

The copper tube is the main nozzle. That is what feeds fuel to the engine from the high speed jet. Put the tube on your spray can of carb cleaner and spray directly into all of the passages (Be carefull and wear saftey glasses, sometimes it likes to come right back at you) then blow them out with your air compressor. I never used the dip, when I was doing mower repair sometimes I did 5 or 6 carbs a day and the dip took too long. I like Barryman's carb cleaner, seems to be the "hottest" one on the market.

 

[Kajun37]

Re: 79 evinrude carb problem(Video)

the problem is i have already done that twice...i have bascially blew a full can+ of carb cleaner through all the passage ways and it still seems like its still clogged...thats why i was thinking about soaking them for a day or so....here are some pics of what they looked like when i pulled them apart for the first time..

 

[reload]

Re: 79 evinrude carb problem(Video)

When you had the carb on the motor, did you ever try to close the intake to the carb off completely and try to start to see if it pulled fuel from the carb. I have had some freck thing happen once where after I closed off the intake and pulled it a few times it started sucking fuel and ran fine afterwards.

Just a thought.

 

[Kajun37]

Re: 79 evinrude carb problem(Video)

you mean like closing the choke all the way? if so yes i've tried that....prob is when you over pump the bulb excess fuel should flow out of the carb but it wont even do that..no fuel is making it out of the bowl it seems like.

 

[reload]

Re: 79 evinrude carb problem(Video)

You can pump the bulb til the cows come home, if the float is not open you will not get fuel (can not get fuel) through the carb. That is what the float is for, just to keep the float bowl full.

I must be missing something.

 

[Kajun37]

Re: 79 evinrude carb problem(Video)

yea your right.. pumping the bulb shouldnt have anything to do with it..but on my merc it does over flow when i pump the bulb too much..flooding the carb with fuel..which helps start the motor very easy....it prob shouldnt be doing that but it works out good for me lol

on this one if we take the float/bulb out of the picture it still wont put fuel into the throat or up to the low speed needle chamber ....

here is where i think i have a blockage...prob is there is no direct access to the holes except through the leadshot holes......this passageways openings are in the middle of the low speed chamber and the high speed chamber making it impossible to stick the carb cleaner tube in them to blow them out.

 

[klicknative]

Re: 79 evinrude carb problem(Video)

Yep, just like Reload said, when the bulb gets hard, the float bowl is full and the needle valve is closed. Try putting your hand over the intake side of the carb and crank the motor. You should fell some vacuum when the motor is turning over. Or, you could put it together (leave the screen off the carb for now) put it in the barrel, open the throttle all the way, prime it with the squirt bottle, put the throttle back to start and see if it will stay running. The rings might be sticky and it's not pulling enough vacuum to pull gas thru the carb at cranking speed. I had to do that with the 5.5 I just got and now it starts right up now. Also does it blow back out of the intake at all? If it does not, that will rule out a bad reed valve.

 

[Kajun37]

Re: 79 evinrude carb problem(Video)

i'll give that a shot.....cant do the hold one hand on carb and crank though...my rewind is broke...so only way to start it is with the emergency rope or what i been using is my power drill with a socket on the flywheel nut ..and i have to used both hands on the drill or it will strip the flywheel nut......but i will bring it to work tommorow and use a high pressure air blower on it and set it in an ultrasonic bath cleaner all day...then install and use the spray mix...

i had actually tried that before...but i didnt fully open the throttle..i just sprayed mix in and choked it......then i took off carbs and spray mix directly into the reed area and it started right away.

 

[reload]

Re: 79 evinrude carb problem(Video)

Using a drill to crank the motor is probably not a good idea, I'm not sure. I think it would take a pretty strong drill to do the cranking which means a low rpm one. Maybe to low, not sure. Repair the rewind.

 

[Kajun37]

Re: 79 evinrude carb problem(Video)

my drill cranks it with no problem....i have the rewind spring on order..it should be here by next friday...

 

[bowhuntrrl]

Re: 79 evinrude carb problem(Video)

Crazy question, but have you done a compression test ????? If so, what are the numbers ???

 

[samo_ott]

Re: 79 evinrude carb problem(Video)

I agree, it sounds like the compression is down if the drill can turn it.

 

[Kajun37]

Re: 79 evinrude carb problem(Video)

around 90 psi on both...but i think it will be better once i can get it running and do a decarb ...its been froze for 4 yrs...i'll prob re-ring it soon though.

 

[klicknative]

Re: 79 evinrude carb problem(Video)

90 PSI is going to make it hard to start. I think you're on the right track with the decarb, it's just getting to run for the first time. I'd use the rope and not the drill, I wouldn't want to be hanging on to it when that motor fires. Also, sometimes when you try priming it like this, crap inside the engine like the stuff in the ring grouves will break loose. If it doesn't go on the first few pulls, pull the plugs and see if that crud has fouled them. Spray 'em off with carb cleaner and air and try again.

 

[Kajun37]

Re: 79 evinrude carb problem(Video)

lil update on my "carb" problem..which turned out to not be the carbs afterall !!! this whole problem was because i wasnt turning the throttle enough to open the back throttle plate to allow air in the intake!!

the other day i took off carbs and sprayed fuel mix into intake/reed area and it started right up....so i figured my carbs were still clogged up...i brought carbs to work and used high pressure air to blow out all passageways....today i finally had a chance to test it out...installed carbs...still wouldnt fire up...hmmm cant be just the carbs then right? so i take carbs off and spray more mix into the intake....starts up first crank! i sat there spraying fuel in intake and it kept running..hmmmm so i said.."whats different than without carbs on?".....AIR FLOW!.....so i put carbs back on and manually opened back throttle plate!..vroommmm!! starts up.... so i check where i had been setting throttle in the start position....but there is alil play in the throttle and the start position wasnt enough!! so i turned it as far as it would go....vroommmm!! started up very quick and easy!!...so basically i wasnt turning the throttle enough this whole time..not too bright!!!....definetly a lesson learned! got a couple things to do with it ..rewind spring,impeller and change gear oil...and its done!

here's a lil video i made of it today...

http://www.youtube.com/watch?v=c68TKmXoMV8

 

[samo_ott]

Re: 79 evinrude carb problem(Video)

Dang, that was a long video! But at the end it looked like no water was coming out of the pee hole? Is that right? Also, what engine is that leaning against the shed in the background?

 

[darrklim2]

Re: 79 evinrude carb problem(Video)

I saw that too. It looked like there was still water coming out of exhaust relief ports but not out of the pee hole????