Exhaust/Header Questions...

[spike morelli]

Riverrunner 1984, I must concur with Mr. Hotwater on your boat's hesitation problem. I have seen people go crazy trying to find a hesitation problem. You wouldn't believe how many people have NEVER cleaned their flame-arrestor on top of the carb. Have your local shop just soak the thing in carb cleaner for a bit . Once rinsed off, it will flow like new again. Start there. Further, you may have picked up some crap in your carb over time. Check your float bowl(s) for debris, proper float level(s) and accelerator pump for operaton. I tend to think it's more fuel oriented over ignition, but I'm not there to know exactly. Overall, I don't think you have a major problem, just a maintenance issue. About tubing headers, ( they are cool looking aren't they), adding them to an existing state of tune will tend to "lean" the fuel mixture the engine sees, due to better removal of exhaust gasses from the cylinders, but, having just said that, will exaggerate a stumble caused by a lean mixture upon acceleration ( if that's what is happening, again, this is a guess). You may want to have your mechanic jet your carb up a few steps with headers. If you go to buy new headers, ask if the manufacturer has different sized tubing diameters to chose from. Large diameter "Racing" style headers will look bitchin' but not deliver the added kick in the rear you may want, if you have a relatively stock marine engine. Opt for the smaller -tubed header set, if offered, and, for the same price, you should get a better running engine. Just my .02 cents

[riverrunner1984]

Riverrunner 1984, I must concur with Mr. Hotwater on your boat's hesitation problem. I have seen people go crazy trying to find a hesitation problem. You wouldn't believe how many people have NEVER cleaned their flame-arrestor on top of the carb. Have your local shop just soak the thing in carb cleaner for a bit . Once rinsed off, it will flow like new again. Start there. Further, you may have picked up some crap in your carb over time. Check your float bowl(s) for debris, proper float level(s) and accelerator pump for operaton. I tend to think it's more fuel oriented over ignition, but I'm not there to know exactly. Overall, I don't think you have a major problem, just a maintenance issue. About tubing headers, ( they are cool looking aren't they), adding them to an existing state of tune will tend to "lean" the fuel mixture the engine sees, due to better removal of exhaust gasses from the cylinders, but, having just said that, will exaggerate a stumble caused by a lean mixture upon acceleration ( if that's what is happening, again, this is a guess). You may want to have your mechanic jet your carb up a few steps with headers. If you go to buy new headers, ask if the manufacturer has different sized tubing diameters to chose from. Large diameter "Racing" style headers will look bitchin' but not deliver the added kick in the rear you may want, if you have a relatively stock marine engine. Opt for the smaller -tubed header set, if offered, and, for the same price, you should get a better running engine. Just my .02 cents

Thanks for the great info. I will def bring this up to the mechanic.
I did have my carb rebuilt and the first time I took it on the water it had the hesitation problem.
Normally, the hesitation happens after it has been idling for a few minutes not if I take off right after I start it.

[Menace Marine]

Thanks for the great info. I will def bring this up to the mechanic.
I did have my carb rebuilt and the first time I took it on the water it had the hesitation problem.
Normally, the hesitation happens after it has been idling for a few minutes not if I take off right after I start it.

Could be idling to rich if that's the case. You could try reving it in neutral a few times to clear it out before you take off. If it doesn't hesitate after doing that I would try leaning the idle mixture a bit.


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[riverrunner1984]

Could be idling to rich if that's the case. You could try reving it in neutral a few times to clear it out before you take off. If it doesn't hesitate after doing that I would try leaning the idle mixture a bit.


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Ok that sounds a bit more like it. I will def try that out.
Thanks again!!!

[rioracr]

remember to lift your cover after fueling and sitting awhile just to get the gases out of the compartment.........

[spike morelli]

You guys, ( well, a few of you anyway ), seem to be concerned with "not enough air' getting to the engine with the cover down, and just now, about opening the cover to vent "gasses". I could be mistake here, but, isn't it a regulation that the manufacturer equip boats with engine covers, with ventilation, usually a scoop facing forward on one gunwale and one facing backwards on another gunwale? Isn't it some sort of regulation that boats built with covered engine compartments be equipped with a bilge "blower", that you run for a minute prior to starting the engine to clear any unwanted gasses from the bilge?( the "blower" switch on the instrument panel). If so, discussion of "no air", or "bad gasses", is likely moot I'd think.

[Bobby V]

You guys, ( well, a few of you anyway ), seem to be concerned with "not enough air' getting to the engine with the cover down, and just now, about opening the cover to vent "gasses". I could be mistake here, but, isn't it a regulation that the manufacturer equip boats with engine covers, with ventilation, usually a scoop facing forward on one gunwale and one facing backwards on another gunwale? Isn't it some sort of regulation that boats built with covered engine compartments be equipped with a bilge "blower", that you run for a minute prior to starting the engine to clear any unwanted gasses from the bilge?( the "blower" switch on the instrument panel). If so, discussion of "no air", or "bad gasses", is likely moot I'd think.

My boat has a bilge blower. But I usually lift the hatch if it has been sitting for a while when I'm on the lake. Doesn't hurt to do this just to make sure all the fumes are all gone.