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Carb bogging issues

fastjeff

Gold Medal Contributor
"I've had this happen to m

"I've had this happen to me twice now: Clean carbs, properly set, idling properly, with the recommended jets. Open the throttle in gear and she bogs like crazy--whack it open and she stalls every time. Ease the throttle open and she'll slowly pick up, then go about her business as usual.

First case was 50 hp carbs on a stock Mark 35A. Latest case is stock carbs on a 650 triple. In the latter case, I have to slap a bit of choke on to get her to rev up in gear--she springs to high revs immediately in neutral, or with my 'test prop' on it (a very low pitch and diameter thingee).

Anyone know how to cure this nonsense?

Jeff"
 
"Jeff, I find sometimes I over

"Jeff, I find sometimes I overthink things and look for a major problem and it turns out to be something minor.

It seems safe to assume that you are not getting enough gas. As soon as either motor came under load, it gagged.

So I'll play the advocate here - see if there was anything common to both motors.

Were you feeding them with the same gas tank? or fuel line?"
 
"Yes and yes. But all my othe

"Yes and yes. But all my other motors don't do that, so...

I'm gonna try adding a 1/4 turn richer on the idle settings and see what that does. (What I really need is an accelerator pump, but...)

Thanks,

Jeff"
 
"Have you replaced the gas hos

"Have you replaced the gas hoses "under the hood" on both of the ones giving you trouble.

Just re-read your post and see that they were both "more mature" models that would have had gas lines built with rubber compounds used long before the advent of ethanol.

If original, they may be restricting themselves from the (inside) as the rubber is breaking down or swelling..."
 
"All new alcohol-proof stuff.

"All new alcohol-proof stuff. Good idea, though. Saw some fuel lines on my kit car fall apart after gas-a-hol got to them.

Jeff"
 
"Seeing as I know very little,

"Seeing as I know very little,but,and this was my experience,when you replaced the fuel lines you didn't by any chance use a smaller bore? Stupid I know,but????
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"No. In fact, I use a size lar

"No. In fact, I use a size larger than normal. And pumping the bulb doesn't seem to help.

Thanks for the input.

Jeff"
 
Another wild theory - couldn&#

Another wild theory - couldn't be a timing issue? Like not advancing under throttle? Pretty sure that opening the carb butterfly under no load will cause the engine to rev up but not while under load - had that problem on a Suzuki once....
 
Ever get this problem fixed?

Ever get this problem fixed?

My motor did something like what you are saying today. Motor ran good got up on plane great than I did a fast idle past some fisherman than punched the motor and it would not wind out. It took prob 2 miles at full throttle than I felt a surge of power and than a little more power and all was good the rest of the day.

I am thinking a stuck float. My motor is a 1989 200 mariner 3 carb

Randy
 
"Winter has put a halt on my e

"Winter has put a halt on my experimenting, but not my intent to cure that problem. I'm told adding another 1/4 turn richer on the idle jets might help, but I'm a bit doubtful.

What I need is someone who knows how to enrichen the mid-range of a Tillotson carb. I'm sure there's a way, and I have a chart showing all kinds of drilled passages on various Merc carbs, so... Another Spring time project.

On Randy's problem, I'd put my $$ on a fouled plug.

Jeff"
 
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