Machanics are stumped

[jbjennings]

Re: Machanics are stumped

I think that Joe Reeves has given some super advice (as usual). That motor has at least 3 carbs, right? It's doubtful that all 3 are boogered up. Follow Joe's advice and find the bad carb and go from there. Also, your first post was a little confusing to me since it had no punctuation. I wasn't sure whether you were doing fine on idle after choking it a couple of times, or the motor was lean sneezing a couple of times and then doing fine as you added throttle.
If it idles nice and low and smooth, then your problem must lie in carb synchronization I wouldn think......
I hope you find the gremlin,
JBJ

 

[Joe Reeves]

Re: Machanics are stumped

Your original post stated "Have a 1985 70 evinrude will idle all day once choking a couple of times while increasing thottle past low speed will run great full throttle."

I have somewhat of a problem understanding what that means. However, I assume that you're saying that the engine has a tendency to die out at some point when throttle is applied.

If so, this is usually caused by either the three carburetors not being synchronized, that is all throttle butterflies shutting to full closure at the same time, and just starting to open at the same time.....

Or the fixed brass high speed jets located in the bottom center portion of the float chambers are fouled (or the wrong size).....

Or the cam/cam roller is adjusted wrong (not where it belongs in relation to the timing) which is forcing the throttle butterflies to open too soon in relation to the timing.

 

[pulpwood]

Re: Machanics are stumped

I will try and explain as good as I can the motor when first cranked will idle fine it is when you give it throttle that it will die or stall out unless you pump the choke on the key switch a couple of times while giving throttle to get to a certain point where it will run fine until backed back down will stall unless pulled all the way back to idle and will idle fine. I have done the linc and sinc all butterflys close and open at the same time, cam on middle carb is set to paper thickness from cam follower inline with the line on cam follower. AS for carbs I started breaking apart again last night pulled out the plugs looks clean inside, all passages clean, the two tubes going up from the float bowl clean no cracks, still put in carb kit to soak again, floats are set correct. Timing is set at 5 deg at idle and 20 deg full throttle. I do appreciate all suggestions keep them coming maybe can get it running, do have someone looking for another carb to test with.

 

[Faztbullet]

Re: Machanics are stumped

I have seen some 3 cylinders over the years that just dont like the factory suggested set-up and like a little more timing before fuel, try opening the roller to a 1/8 gap and retest.

 

[ezeke]

Re: Machanics are stumped

What are the part numbers stamped on the carburetors and what are the numbers stamped on the high speed orifices?

 

[nymack66]

Re: Machanics are stumped

Your original post stated "Have a 1985 70 evinrude will idle all day once choking a couple of times while increasing thottle past low speed will run great full throttle."

I have somewhat of a problem understanding what that means. However, I assume that you're saying that the engine has a tendency to die out at some point when throttle is applied.

If so, this is usually caused by either the three carburetors not being synchronized, that is all throttle butterflies shutting to full closure at the same time, and just starting to open at the same time.....

Or the fixed brass high speed jets located in the bottom center portion of the float chambers are fouled (or the wrong size).....

Or the cam/cam roller is adjusted wrong (not where it belongs in relation to the timing) which is forcing the throttle butterflies to open too soon in relation to the timing.

Please read Joe's post it worth its weight in gold ..

 

[pulpwood]

Re: Machanics are stumped

I am in process of starting over carbs broken down and soaking, all plugs and fixed jets are out checking every detail I can. Will reset linc and sinc try playing with timming. I will also look at numbers on jets to make sure all is correct. Thanks

 

[pulpwood]

Re: Machanics are stumped

What are the part numbers stamped on the carburetors and what are the numbers stamped on the high speed orifices?

carb# fl 328568 high speed # looks like 52D set idle screw on end is #42 jet on side not sure what it is call being it does not show it in any diagram is #68 I did pull out all plugs no trash soaked in carb kit any way. Not for sure if these jets are right for these carbs.

 

[LV2BT]

Re: Machanics are stumped

I'm not a 2cycle specialist by any means much less an outboard mechanic but I ran into a simlar issue with a snomobile engine a number of years ago. Would idle fine forever and would run WOT no problem once you got it going with choke. Turns out one of the main crank seals was damaged/leaking enough to muck with the fuel/airflow. I can only assume at the higher RPM's the crank case would develop sufficient ?vacuum? to negate the leak. Only reason I found the problem was that it eventually became harder and harder to get it over the "hump" so to speak with the choke between idle and WOT. After rebuilding the carbs several times (and even changing them out with known good ones) I finally gave up and dissasembled the entire engine at which time the bad seal was found. That's my 2c for what its worth.

 

[ezeke]

Re: Machanics are stumped

The fixed high speed jets on early production 1985 70HP models should all be 52D and on the late production models should be 57D. [Unless your motor is set up for high altitude]

All Low speed jets should be 28M on either production.

The numbers stamped on the carburetor bodies should be: early = 395579 & 395578; late = 396964 & 396965.

Only the 75HP models should have the carburetors with adjustable low speed needles.

 

[JustJason]

Re: Machanics are stumped

keep in mind not every carb is rebuildable. When you get the carbs back on and the engine running spray some foaming oil around the throttle shafts to see if they are leaking.

 

[pulpwood]

Re: Machanics are stumped

I checked for other # and got this one from inside float chamber # 328568 AS for cracked seal on crank I have also heard of that but don't know how to be sure without tearing down block I know I don't have any oil on my stator and coil from top seal.This might be last resort to go into block

 

[ezeke]

Re: Machanics are stumped

I checked for other # and got this one from inside float chamber # AS for cracked seal on crank I have also heard of that but don't know how to be sure without tearing down block I know I don't have any oil on my stator and coil from top seal.This might be last resort to go into block

I think that 328568 is a casting number because it does not match anything.

The jets you are describing sound like a 1984 carburetor; what is your model number?

 

[pulpwood]

Re: Machanics are stumped

model of motor is a E70ELCOS I know I haven't found a carb just like the one I have. Might have come off of another year model

 

[pulpwood]

Re: Machanics are stumped

I think that 328568 is a casting number because it does not match anything.

The jets you are describing sound like a 1984 carburetor; what is your model number?

You are right looked up 1984 model carb and looks just like mine also shows the same size jets as mine but mine is a 1985 according to model #E70ELCOS but can't imagine that to be my problem I know I pulled out the carb from soaking and pulled all plugs and eveything looks good no damage or blocks. Do you think it could be my crankcase seals.Thanks

 

[ezeke]

Re: Machanics are stumped

If those are 1984 carburetors, then the jets that you have are correctly numbered. The one at the top (42) is the intermediate, 68 on the side is the low speed and 52 is the high speed in the float bowl.

You can check that the orifice openings are correct using the base of drill bits.

# 42 use #58 drill bit
# 68 use #51 drill bit
# 52 use #55 drill bit

 

[pulpwood]

Re: Machanics are stumped

If those are 1984 carburetors, then the jets that you have are correctly numbered. The one at the top (42) is the intermediate, 68 on the side is the low speed and 52 is the high speed in the float bowl.

You can check that the orifice openings are correct using the base of drill bits.

# 42 use #58 drill bit
# 68 use #51 drill bit
# 52 use #55 drill bit

Ok checked with drill bits all jets seem to be right but if you think new jets would help I'm willing to try. There's a guy here who races boats named larry mumford thinks he has some carbs laying around somewhere but gone to races said he would look when got back. Only thing I have left to try before breaking down motor.

 

[Mohawkmtrs]

Re: Machanics are stumped

Ok checked with drill bits all jets seem to be right but if you think new jets would help I'm willing to try. There's a guy here who races boats named larry mumford thinks he has some carbs laying around somewhere but gone to races said he would look when got back. Only thing I have left to try before breaking down motor.

Before tearing down the motor perform a crankcase pressure test.

If it loses pressure, you have a leak somewhere...spraying soapy water at/around all gaskets, crankcase halves (anywhere a leak can occur) will identify the leak.

 

[pulpwood]

Re: Machanics are stumped

How do you perform a cranckcase presser test not for sure if I have what I need

 

[reeldutch]

Re: Machanics are stumped

haha crankcase pressure test.

how do you close the ports???
you will have to take the block of the motor and make intake and exhaust airtight.

i would just replace the seals upper and lower.

before that run the motor and spray carb cleaner around the carburators trothle shafts, see if it changes the engines rpm.if it does you found the leak. if it doesnt spray carb cleaner around the crankcase mating surface, listen for rpm change.

if none of these tests show any change and you are 100 % sure the carbs are good and engine timing and link and sync are good you want to look further at the crankcase lower and upper seal.

forget pressure testing just replace the seals you will have to remove the powerhead at that point anyway.