1995 Evinrude 150 V6 Looper, One Last Issue

[s.wxman]

I'll try to keep this short.
Motor would just instantly die at speed. Would start back up and run fine. Took to two Evinrude mechanics. Ended up with 8 (yes eight) rebuilt carburetors and a new fuel primer bulb. Compression checked good. Each time upon return the boat never made it across lake without the instant dieing. I got some manuals and troubleshot problem to Powerpack. Replaced powerpack, optical sensor, plug wires and plugs (QL78YC). Even did a decarb just for grins. Motor didn't die instantly at speed anymore, but had problem with rough running or dieing during throttle advance. Link/sync was way off; butterflys opening well before timing was being advanced. Not sure if that was the Evinrude mechs or me somehow when I was checking timing and setting idle after powerpack install. Reset link/sync best I could do.
Now, first start of day is fine, motor idles great and the SLOW stuff works. Runs great, good holeshot, no hesitation on throttle advance, etc..., just great.
UNTIL, the motor is shut down for 20-40 mins and then restarted.
Short stops are fine, like trading skiers or tubers. Many, many start stops with no problems, fast idle for 5-6 secs and then idles great and runs great just like supposed to. But if I take a break of 20-30 mins skiing, or want to change fishing spots after 40 mins of slow fishing, the motor will start, but sputter and die. Sometimes it will continue at idle, although rough, but then die when put into gear. Or, if I try to advance throttle with transmission disengaged, it won't take the gas and dies. After 4 or 5 attempts, I can usually get it to take the gas with the trans disengaged, it will smooth out and I can return to idle and continue on my merry way until the next stop of say 20 mins or more.

Ran through 3/4 tank of gas yesterday and the only hiccup all day was after our one 25 min break to let the kids rest and get a drink. All the other start/stops were fine. The motor, I think, runs really strong.
Where do I start on troubleshooting this one last problem? Cold starts good. Hot starts good. Medium starts not so good.

Thanks to all,
Wxman

 

[s.wxman]

OK, I went out to look over the motor again this morning and found something. I took off the air silencer and checked the torque on the carb mounting screws I could reach. A couple turned a little, but they were all probably within the manuals spec. With the silencer off I pumped the primer bulb and was going to see how long it would hold pressure, see if any carbs overflowed, etc. As soon as the bulb got a little stiff fuel gushed out of the fuel filter. Quite a bit of fuel, tablespoons at least. It was leaking where the filter assembly screws in, not from where the hose connects to filter. The connecting nut was very tight so I removed the filter. The gasket (not the o-ring) was in the wrong place and completely wrinkled and torn. It was between the nut and the filter instead of between the filter and the case.
New assembly, gasket and o-ring on the way.
Now the question is, should I wait and see what happens with this fixed? Could this be the medium start problem or do I need to go ahead and troubleshoot some more? If it makes sense that this could have been the issue (fuel leaking, air getting in) then I am more than happy to fix it and try it again before doing more work.
Thanks again
Wxman

 

[Chris1956]

Wxman, It sounds like you are down to a problem that lots of us face with that motor. The warm restart issue. If your new gasket fixes it, let me know, as I will then try it. If not, let me know what does fix it, if you find a fix....

 

[s.wxman]

OK, may be too early to declare total victory, but must be getting close.
While waiting for the filter gaskets I decided to look everything over that I could. I found that the recirculation system did not check good on two cylinders. Since I had to take more apart I decided to do a bit more as preventive mx.
Two port cyls had bad recirc check. I replaced all nine check valves on port side. Two of the valves in the block were bad, not the ones in the intake. New gaskets and o-rings on anything I disassembled.
Rebuilt vapor pump, new float valve/seat in vapor sep and new seals and o-rings throughout that sys. Float valve looked a little suspect.
Went over all fuel and oil line connections. Added/replaced some clamps.
Added an anti-siphon valve at tank in hopes of keeping fuel in/air out of fuel line longer.
Complete link/sync after assembly.
Took it to lake today and it was hot (90) and humid. Motor ran great. Increased idle timing one notch on the water. Idle smoothed out and I have about 650 in gear and 900 in neutral. No restart issues at all today, however, I didn't have any extended sit times between starts. Six to seven minutes vs 30 or 40 (too hot for me to sit still any longer today but plan on fishing Mon.)
Also, my bulb still goes soft in just 45 mins or so. Can't figure out where that problem is unless it is internal to VRO. That might be a winter project as the VRO is original and 19 yrs old.

 

[Chris1956]

OK, Sounds like you fixed some issues. I think more testing will be necessary to prove the warm restart issue is fixed. Let me know how it goes. I will guess the recirculation valves are the main culprit for the warm restart issue.