Looper won't run with cowl on

[jmadisonbiii]

I have an older Johnson V-4 85 looper. It has always run well with minimal maintenance and is on an aluminum boat I use a few times a year. Got it out a couple of weeks ago to go duck hunting, put it on the muffs and it ran fine...until I put the cowl on, whereupon it would die out. Everything I've read on this points to a leak at the adapter to powerhead gasket, causing exhaust gases to be sucked back into the motor, starving it of oxygen. Should I be looking at anything else here, or just pull the powerhead and replace this gasket? Thanks in advance for any help.

[RRRevinrude]

You need to find the leak--could be the exhaust cover leaking or powerhead gasket or adaptor housing...and just for the record an 85 v-4 is a cross flow not a looper....

[FlowMaxx]

If it is a newer motor (lower cowl pan) with an older cowl there is no way for air to get in. Newer cowls breath through the top rear of the cowl, the older ones breath from an opening underneath the carbs. This is if it is a cross as RRR suggests....

[jmadisonbiii]

It is a crossflow, a 1979. Sorry for the mix-up. I guess the best way to find the leak is with soapy water?

[mn808gade]

run it in the dark-easier to see leak.also easier to see coil sparks to ground in darkness,runnin on muffs,sometimes i have helper hold blanket/tarp in daylite-th

[Superbender]

Make sure the coil wires aren't shorten out

[flabum1017]

If it takes a couple minutes to die out, the it will be a bad powerhead base gasket or chest gasket. Could also be corroded castings. If it dies out real quick, then the plug wires are getting shorted out on the hood clamps.

[jmadisonbiii]

OK I finally got a chance to run it in the dark, and yall were right, there is arcing at the cowl latch at the bottom right (#3?) cylinder. None of the wires look bad, but I figure the insulation on the plug wire is worn or damaged. What is the normal fix-a new coil, or simply repair the wire?

[nymack66]

Check your Carbs stuck float or excessive fuel ..With the cowl off its leaning out and running fine......