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Fuel issue, completely lost

S

SJAJ

New member
Hello all, new here but have picked up good info from other threads. Sorry for the length this might turn out to be...

Got a 70TLESB with the VRO pump converted to premix. Took the time over the winter to rebuild the carbs as they were always rough and had to run slightly rich for optimal reliability. Looking at everything upon tear down, it was all needed. Found 2 cracked float bowls and everything was pretty dirty. Cleaned everything thoroughly, set the float and verified the hinge was smooth and no sticking with the needle and seat. After mounting and hooking up linkages, verified the carbs were synched up. Also rebuilt the electric primer pump that was cracked and leaking as well. Did not touch anything else on the motor.

Engine fired up on muffs with initial setting of two turns out on the slow speed needle valve (the only adjustment). Had a heck of a time trying to dial in the low speed, needle seemed really touchy to slight changes. Long and short got to a pretty good idle finally. Goosed the throttle a little and had good reaction. Got it out on the water couple days later and seemed to have a hard time starting, seemed a bit rich. Got 200 yards from the launch and slowly throttled up. The more the throttle increased the more the engine seemed to be flooding and choking itself out and then stall coming back to idle. Back on the trailer and on the driveway got the muffs back on. Fired right up but again slowly throttling up it poured smoke and choked itself out bringing it back to idle. I also noticed a lot of black gunk coming out the exhaust and on the driveway. Upon shut down, noticed the inside of the prop was loaded with black residue. also noticed the two rear facing exhaust ports near the top of the rear were unusually black along with the three screened ports above where the prop shaft would be in the lower unit. Lastly, the primer bulb (which is new also) is not getting hard. I can see fuel moving in the fuel filter (clear glass) but never firms up. And as much as I pump, I see no fuel in the carb throats and no fuel leaking anywhere or even a smell of fuel, so I have no idea where it is going!

Going a bit nuts with this, so any suggestions or help would much appreciated!! Thanks!

Steve
 

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Did you install new fuel bowls ?----If yes did you swap in the high speed jets from the old?----Did you install a new or used FACTORY fuel pump or something cheaper?-----Why is the VRO still there.------And the electric primer is a valve and NOT a pump.----Red lever on the primer in the correct position.-----Post the actual compression values here.
 
Thank you for the quick response.

Yes, put on three new fuel bowls and no I did not swap in the old jets, I used the new ones with the rebuild kit. (Johnson OEM kit)

For clarification, I actually did not do the pump swap, purchased the boat with it done. I know the boat is not rigged with oil tank. Doing some research, Marine Engine has the OEM VRO fuel pump and there is also something called VRO premix conversion pump https://www.marineengine.com/newparts/part_details.php?pnum=OMC5007422. This is also an OEM item. Looking at the pump on my engine it appears it is the OEM, but I cannot be absolutely sure, I also have not been able to find a cheaper knockoff.

Yep, I misspoke, didn't catch that one on the primer. The electric primer lever is correctly positioned, just reverified.

Compression is as follows from top to bottom; 120, 123, 128.

Thanks again.
 
Thanks! Yeah, I need all the beer tokens I can get! This has been so frustrating. I mean the boat ran, albeit a bit rough, thought I was doing the right thing with the carb rebuilds, but it’s been a nightmare ever since. Don’t know if I should pull them off and recheck everything, but I keep going back to there’s no fuel in any of the carb throats when I pump the primer. No fuel leaking anywhere, where the heck is it going? I see it flowing through the fuel filter. Could the pump diaphragm be ruptured? I read fuel can get right into the crankcase causing a heavy rich condition, is there a way to check that? Any recommendations on a diaphragm pump that would work and fit on this motor? Thanks!
 
Roger that, no problem. All parts were from Marine Engine.

3 Carb rebuild kits, Johnson PN 0396701. 3 fuel bowls, Johnson PN 0330195 and Electric Primer Service Valve Kit, Sierra PN 18-7044-1.
 
Simple fact just for you.-----There is a float valve in that kit.----There are no jets in that kit.-----So do you have high speed jets in the new bowls , yes , no or no idea ????
 
Rebuild kits come with inlet needles & seats.
The jets Racer asked about are high speed jets in the bottom of the fuel bowls. They are accessed thru the drain screw hole. New bowls would not have jets installed - you swap your old ones over.
 
Thanks guys....So I will say with a strong degree of confidence that the high speed jets are not in the new bowls. I have one of the old bowls sitting on my desk this morning with the jet still installed. I completely overlooked that with the new bowls, I thought I had covered everything looking at the carb drawings here. Don't know what's worse, the fact I overlooked that, or the fact that I threw away $80 worth of jets when I tossed the 2 cracked bowls 😆. But in all honesty, I likely would have ordered and put new ones in when I rebuilt them had I caught that (and jeez, 65 bucks for a specialized orifice service tool!?). So yeah, the light bulb came on after reading those posts...throttling up and having the engine flood and choke out makes perfect sense with no HIGH SPEED jets installed! Doh!

Getting things ordered this morning. Will report back here on the outcome.

Thanks for all the timely replies and help, never would have gotten to this point and likely ended up in an insane asylum...
 
You could probably make the tool to remove the Jets. Go to your local Home Depot buy an appropriate size screwdriver than either a bit of work with a file or grinding wheel to make an exact fit
 
Jets are not $80 if you have same patience and look for used.----Supplied an individual with 4 used ones for a V-4 a few years ago.-----Also threw out the bowls with jets in them.-----Mistake will likely be made again soon.
 
Ha! I never learn from my mistakes, something my wife will remind of every time. Already been checking around seen them as cheap as $20 a piece so far
 
Checking back in. Got the parts in and everything back together and I have to say it’s amazing how well things work with all the parts installed correctly!! 😂 Dialed everything in and running well, will be hitting the water tomorrow.

Thanks for all the input racer.
 
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