'84 Johnson 25 hp

[Rambo58]

I have a 25 hp Johnson I just purchased recently. I ran it in the test barrel earlier today and it ran great after a few adjustments with the hood off. When hood is installed it will run good for a short time when it starts then won't idle up anymore than start speed with the throttle wide open. What is causing this ? Is it the exhaust smoke choking it out bc when I idle it down it seems to clear up a bit. If u remove hood at wide open throttle it is wide open when it gets the first pull of fresh air. My question is is this a common issue with these running them in barrels? Thanks

 

[joereeves]

In a barrel, with the hood installed, the engine draws its exhaust directly into the carburetor... that's a no no!

 

[Rambo58]

That was what I was thinking is going on. So running it on the water it shouldn't do this ?

 

[Boobie]

Yes..........

 

[Rambo58]

Thanks for the help.

 

[timguy]

Once you get it out on the lake, whether the cowling is on or off will sometimes even change the low speed mixture. Some motors have the air intake down below and others have it in the cowling. Often times the lower positioned intake holes will draw contaminated air at trolling speeds thereby affecting the low speed mixture. The worst thing outboard engineers have done is provide intake openings big enough for a mouse.

 

[kimcrwbr1]

I have seen the air intake plugged under the handle of the cover with bug nests plugging the holes something to look at.