9.5 Evenrude runs bad with cowling on

[jbabcock]

Just a quick confused question here i have a 9.5 evenrude and when the cowling is off it it runs like a champ however as soon as i put the cowling back on it runs really boggie any ideas? it is a 1969 I have the needle turned out about 3/4 of a turn what is what I normally run them at but I have never had this issue before.


Thank you
James

 

[fireman57]

Re: 9.5 Evenrude runs bad with cowling on

Classic sign of your base exhaust gasket being bad. The one at the bottom of your engine where it connects to the midsection. It doesn't run good on CO2.

 

[ultra353]

Re: 9.5 Evenrude runs bad with cowling on

These motors are notorious for under the cowl exh leaks. Could be shift shaft seal, rear rubber exh relief hose. Most start out at 1 1/2 turns out on the needle and in 1/8 increments turn the needle in, let motor responed for 10-15 secs, rpms should increase, lower your idle down a bit. Repeat this process until motor has a slight misfire- its running too lean, turn needle out to a bit to get your smoothest idle. This procedure should be done on a boat ,in fwd gear and motor up to operating temp if possible. If at home using a barrel-put in gear and motor up to temp.

 

[boobie]

Re: 9.5 Evenrude runs bad with cowling on

When we had this problem years ago and the seals were NLA we used to drill some holes in the front and back of the hood and they ran fine.