Exhaust/Header Questions...

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06-02-2014, 10:04 AM
riverrunner1984

2 Attachment(s)

Exhaust/Header Questions...

As some of you know, I am not too mechanically inclined and had a questions regarding differences between these two types of headers.

Currently I have this type of set up. (not my boat, just an example)
Attachment 41462

Was wondering if there is a performance difference going to this type of set up or is it just for aesthetics?
Attachment 41463

Main reason for asking.
Last time I had my boat out, once in a while when I gave it gas, it would studder and take a while to get going (not all the time, just sometimes)
Someone told me that the boat is burning too rich and I should take my engine cover off.
When I see other jet boats out there with the engine cover off, I see the headers over the stern.
Was wondering if I would have to put these on if I took the cover off.
If so, is there a performance difference.
I have a 19.5ft jet boat with a 454.

With my limited mechanical knowledge, I hope my question makes sense. lol :D
Thanks in advance guys.
06-02-2014, 10:14 AM
Sharp shooter

Quote:

Originally Posted by riverrunner1984

As some of you know, I am not too mechanically inclined and had a questions regarding differences between these two types of headers.

Currently I have this type of set up. (not my boat, just an example)
Attachment 41462

Was wondering if there is a performance difference going to this type of set up or is it just for aesthetics?
Attachment 41463

Main reason for asking.
Last time I had my boat out, once in a while when I gave it gas, it would studder and take a while to get going (not all the time, just sometimes)
Someone told me that the boat is burning too rich and I should take my engine cover off.
When I see other jet boats out there with the engine cover off, I see the headers over the stern.
Was wondering if I would have to put these on if I took the cover off.
If so, is there a performance difference.
I have a 19.5ft jet boat with a 454.

With my limited mechanical knowledge, I hope my question makes sense. lol :D
Thanks in advance guys.

First off, these are not "headers".
http://www.hotboat.com/frm/attachmen...2&d=1401728261

Headers allow an engine to push out the exhaust gas easier making for more efficiency. With a stock engine they won't help all that much (if at all).

You need to take your boat to a pro and have it tuned. Lack of headers aren't your problem. If your engine is of the high performance variety, headers will allow it to work better.
06-02-2014, 10:16 AM
riverrunner1984

Thanks for the info.
Thats why Im asking here. I want it to look like I know a little bit when I go to a place.
06-02-2014, 10:47 AM
riverrunner1984

When I typed in headers for sale on CL...
these came up. Look like what I posted in the pic kind of????

Just trying to get some clarification

http://inlandempire.craigslist.org/boa/4497735813.html
06-02-2014, 12:12 PM
Sharp shooter

Quote:

Originally Posted by riverrunner1984

When I typed in headers for sale on CL...
these came up. Look like what I posted in the pic kind of????

Just trying to get some clarification

http://inlandempire.craigslist.org/boa/4497735813.html

You posted 2 pics in your first post. Top pics shows a single marine exhaust manifold lower pics shows both OT headers. The craigslist ad is for 2 types of headers. One set of OT's or over transom the other is a through transom header.
06-02-2014, 02:17 PM
HotWater

If it just started the problem last time you took it out it has nothing to do with the motor cover. Probably carb, ignition or both.
06-02-2014, 09:21 PM
Menace Marine

Quote:

Originally Posted by HotWater

If it just started the problem last time you took it out it has nothing to do with the motor cover. Probably carb, ignition or both.

Agreed. The motor when properly tuned should work flawlessly and not stutter or bog. Motors need air to run. I'm not sure how sealed your engine compartment is but if it worked good in the past then this isn't your issue. Ignition may need a tune up or carb adjusted or rebuilt.

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06-02-2014, 09:24 PM
Menace Marine

If you still suspect the motor is not getting enough fresh air you could always prop the engine hatch up slightly and see if the situation improves. It shouldn't take much and obviously use caution to not loose the hatch or fall into the belts etc etc.

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06-02-2014, 09:40 PM
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
06-03-2014, 07:47 AM
riverrunner1984

Quote:

Originally Posted by 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

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.
06-03-2014, 08:54 AM
Menace Marine

Quote:

Originally Posted by riverrunner1984

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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06-03-2014, 09:08 AM
riverrunner1984

Quote:

Originally Posted by Menace Marine

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!!!
06-04-2014, 08:24 AM
rioracr

remember to lift your cover after fueling and sitting awhile just to get the gases out of the compartment.........
06-04-2014, 08:49 PM
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.
06-04-2014, 09:11 PM
Bobby V

Quote:

Originally Posted by 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.

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.