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Question on Evinrude 150 Looper Crankcase Casting

Plastic carb bowls do not use washer. The clearance for the needle travel is impinged and can cause lean conditions at mid to top end operation. Back to your problem of no fuel to cylinders. On these everything comes from throttle body. Fuel feed to carb, idle and intermediate carb signal all come from here. If you have incorrect mounting O-ring, calibration gaskets leaking on throttle manifolds or carb side plates it will not pull fuel thru carb circuits
 
racerone said:
The plastic housing is sufficient to seal this assembly.-----And the needle and seat is common for many , many motors.----Therfor the washer is included !!!
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Washers removed, new needle / seats, new floats, all new seals / gaskets, etc. No progress….same problem.

Question: Even if electric primer is defective, wouldn’t the motor continue to run after it starts by squirting fuel into carb throats? Or, does electric enrichment continue for some specified time?
 
The primer only does something when the key is pushed in.-----Unless of course if the red lever is in the wrong position.
 
Thanks.

Then, if engine starts by squirting fuel into carbs, but won’t continue to run, it follows that the problem is that fuel is not being drawn into crankcases. This would be true, regardless of what method is used to start it.

So, problem is likely one of the following: inadequate vacuum to draw fuel into crankcases (not likely in all 6 crankcases); fuel restriction in carbs (all 6 carbs?); inadequate fuel supply in carb float bowls; or severe or multiple air leaks.

I set float drops to Evinrude specs (11/16" - 1-1/8" to top of float from bowl gasket) with carb in normal upright position. Top of float was set even with bowl gasket with carb inverted. Any problems there?

Tough to troubleshoot an air leak on an engine that won’t run. Shouldn’t I consider doing a leak-down test? If so, how do I do it on this engine?
 
Will do.

Interesting that you mention stator. The original tach quit functioning. RPM reading was erratic and check engine light remained on even if motor was not running. Recently, the RPM stopped registering and the needle broke off tach. So, I replaced the tach. System check now functioning, but no RPM. I believe the signal for tach is generated from stator via the VR/rectifier. Since both stator and VR/rectifier are new, I presumed the problem was in wiring somewhere. Just haven’t addressed it, given the higher priority engine problems. Although I understand the tach operates on AC current converted by the rectifier, it does sound suspicious?

Thanks. Any direction is appreciated.
 
racerone said:
Do a complete test on the stator.-----Ohm check all windings and report the values you see.
Click to expand...
Here’s the results for charge coil test, presuming I did them correctly. Tests were performed on leads in starboard connector between stator and power pack.

Both motor and accessories batteries were “on.” I used a remote starter. Ignition key was off. I connected a DVA to my digital volt/ohm meter for stator voltage ground and output tests.

Ground Test:
Ground - Brown: .7
Ground - Brown/Yellow: .5
Ground - Brown/Black: .5
Ground - Brown/White: .5
Manual Diagnosis: Any reading indicates charge coil is grounded. Locate and repair ground or replace stator assembly.

Output Test:
Brown - Brown/Yellow: 132
Brown/Black - Brown/White: 125
Manual Diagnosis: If less than 150 volts, check condition of wiring and connectors.

Ohmmeter Test:
Brown - Brown/Yellow: 552
Manual Diagnosis: 550 +/- 55 ohms. OK

Ground - Brown: OL
Ground - Brown/Yellow: OL
Manual Diagnosis: No reading. OK.

Brown/Black - Brown/White: 530
Manual Diagnosis: 550 +/- 55 ohms. OK

I should mention; stator was replaced a year ago, but has virtually no hours on it.
 
Given the details of the start/no run scenario earlier described, I was convinced I was dealing with fuel deprivation. Question is: Even If stator or stator connections are found to be defective, could that prompt the condition I’m experiencing? Why would squirting fuel into carb throats prompt an instant start, but not continue to run?
 
Your motor would start and run on any of 3 of 6 of the cylinders.------I doubt you have 6 bad carburetors.----I doubt you have 6 bad crankcases.-----I doubt you have 6 bad cylinders / pistons.-----But good luck with your trouble shooting.
 
;
faztbullet said:
Forgot to do the power coil reading...org to org/blk. Your stator reads so far are good if plugs where in
Click to expand...
faztbullet said:
Forgot to do the power coil reading...org to org/blk. Your stator reads so far are good if plugs where in
Click to expand...
POWER COIL TEST 12/31/2023

Ground Test:
Ground - Orange: .1V
Ground - Orange/Black: 0V
Manual Diagnosis:
Any reading indicates power coil is grounded.
Locate / repair ground or replace stator assembly.
If no reading go to Output Test.

Output Test:
Orange - Orange / Black: 53V
Manual Diagnosis:
If less than 50V check wiring and connectors.
If good, go to Ohmmeter Test.

Ohmmeter Test:
Orange - Orange / Black: 50 ohms
Manual Diagnosis:
Reading should show 55 +/- 10.

Test for Grounded Condition:
Ground - Orange: 0 ohms
Ground - Orange / Black: 1.0 ohms
Manual Diagnosis:
Any reading indicates power coil or leads are grounded.
Locate / repair ground or replace stator assembly.
 
I compared manual test values (above) to CDI specs “Johnson/Evinrude DVA Voltage and Resistance Chart” specs. CDI listed DVA value for Orange-Orange / Black as 11-22V. Likely, that may not be apples to apples, but don’t know.
 
Tested electric primer. First by opening valve (pointer up) and pressurizing hand primer….full flow from valve. Also had full flow through fuel lines to manifold inlet fitting. Blew thru lines to assure manifold fittings were not blocked. Tested key-in solenoid….worked.

Drained carb float bowls to check for quantity and color of fuel. All looked good with adequate fuel.

Pulled plugs to check for fouling or wetness. They all looked new (they were replaced last week).

So, fuel to carbs…. and fuel to manifold with electric primer, but wouldn’t start. Air/fuel mixture screws were originally set to 5 or 5-1/2 turns out. In light of suspected lean condition, I readjusted to 6 turns out….and later tried 7 turns out….no difference. Sprayed carb cleaner (a no-no) into (2) carb throats….started…and ran a few seconds until spray was combusted. Seems there is no fuel getting to crankcase. I tried to see if fuel is being atomized in carbs, but couldn’t tell. Covering carb throats with my hand while cranking caused fuel to be drawn into throats. I would think that’s an indication of adequate vacuum from crankcases….enough to draw fuel from carbs.

Just for giggles, I even tried manually retarding timing…..no difference.

Carbs rebuilt (3X). All carbs, throttle bodies, and manifolds thoroughly cleaned and reassembled with new gaskets & seals. Leaf valves were checked. Manifold check valves tested per OMC manual procedure (hope I did it correctly). New exhaust recirc hoses.

If fuel is getting to carbs, but not into crankcases, seems only a few possible scenarios:

1. Fuel is restricted in idle circuit of rebuilt carbs….but all 6??…..and after replacing with new float bowls, cleaning & rebuilding?? If so, where could restriction be? All new needles/seats and new floats set to OMC specs. All orifices cleaned and clear, including intermediate and high speed jets (which shouldn’t affect starting nor idle). Of course, all new seals & gaskets. Fender washers added to carb side covers to promote even pressure on sealing surfaces.

2. Air leak reducing crankcase vacuum and preventing fuel from being drawn into crankcases….at all ports?? What would be common to all. crankcases? It’s been pointed out that engine should start and run on 3 cylinders, regardless how badly it may run. I tried opening throttle plates to varying degrees. Only difference was a throatier sound with throttle plates open.

Is it possible that fuel is reaching crankcase, but a weak spark is causing the problem, and still strong enough to fire a more volatile fuel (carb cleaner)? I tested spark.. Jumped 1/4" gap. Although it’s white/blue, not certain it looked that strong. Could be the tester. As another person said, I’m now chasing my tail.

Not certain where to go next.
 
racerone said:
Spatk should jump a gap of 7/16""----Look into ignition issues.
Click to expand...
Thanks. Will give it a shot.
Do you know which ignition component could be damaged from cranking engine without grounding plug wires? I read that could happen after pulling plugs to check compression. Could have been a big error! Guessing it was power pack.
 
As previous posted make sure you have correct mounting o-ring on carbs and calibration pocket gasket is good. If leak in either the idle circuit will not get a strong signal to pull fuel.
 
faztbullet said:
As previous posted make sure you have correct mounting o-ring on carbs and calibration pocket gasket is good. If leak in either the idle circuit will not get a strong signal to pull fuel.
Click to expand...
Both components are brand new on all 6 carbs. No way to check that I know of, unless I disassemble. I tried spraying carb cleaner around seams of carbs while cranking. No difference.
 
faztbullet said:
As previous posted make sure you have correct mounting o-ring on carbs and calibration pocket gasket is good. If leak in either the idle circuit will not get a strong signal to pull fuel.
Click to expand...
Presume when you say o-ring, you’re referring to the (string-type) seal between the carb body and the throttle body. Correct?

My carbs bodies are PN 436797. Evinrude carb kit instructions clearly spec the use of seal PN 344046 (Black). Per instructions, I assembled carbs using that seal. Yes, I understand the possibility of assembly error, however unlikely I think that is in this case.

When comparing the black seal (PN 344046) and the brown seal (PN343613), the configurations appear to be identical, other than color. Curious, what’s the difference between the two seals. Just wondering if there may have been some revision in PN’s. Probably grasping at straws, but one never knows.
 
faztbullet said:
Here ya go...

View attachment 31782
Click to expand...

Yep, same instruction sheet I used.
I was just wondering what the difference is between PN 344046 (black) and PN 343613 (brown). I overlayed the two seals and they appeared to be identical.
Btw, I highly doubt I installed the seals incorrectly. What is possible is that there may be some warpage in the carb bodies. As previously posted, the original float bowls were warped, so I replaced them with new float bowls, but not the bodies.
Got any ideas on how to make-up for warpage with gasket sealer or some other material, in lieu of sanding…..or worse yet, replacement?
 
This gasket can cause your problem ...
0340657.jpg

Along with the improper cover plate gasket..
0341085.jpg
 
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