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Idiling the engine in a boat
I have another question...if i fix flooding what is the best way to idle the engine in a boat.I need to load the engine and find the highest vacum on the manifold am i right???
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Ive done that buy just dropping the boat into the water still tied down to the trailer during the week when there is no traffic at the ramps to deal with.....
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Originally Posted by Wally
(Post 4831973)
Ive done that buy just dropping the boat into the water still tied down to the trailer during the week when there is no traffic at the ramps to deal with.....
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Originally Posted by Zole
(Post 4831976)
I've never done that..my questione is does the clutc need to be plugged in to make load on engine
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Originally Posted by Wally
(Post 4831977)
If you mean the outdrive shifted into gear...yes..... it helps dial the motor in a little better when under a load like that. You can get a little bit of a load on the engine even on the trailer when shifted into gear....its just more of it in the water when the propeller has bite into the water.
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Idle mixture screws, yes, Typically highest vac,in neutral, then richen idle screws 1/4-1/2 turn will give best idle in gear and transition from idle to lower throttle.
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Originally Posted by SB
(Post 4831982)
Idle mixture screws, yes, Typically highest vac,in neutral, then richen idle screws 1/4-1/2 turn will give best idle in gear and transition from idle to lower throttle.
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Originally Posted by Zole
(Post 4831989)
aha....highest in neutral then 1/2 1_4 richer(screw aut) that would be the best set up?
underlined and bold. :) : wink |
Originally Posted by SB
(Post 4831990)
Typically.
underlined and bold. :) : wink |
Originally Posted by Zole
(Post 4831991)
yust one more question...what do i do with the screw that pushes the trotle blade..what is the starting point
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As you make adjustment to the mixture screws, give it a few seconds to find the new setting, then adjust the idle speed screw (throttle plate) to the recommended idle speed, usually around 700-800 RPM in gear. Repeat until motor is happy with vacuum and idle.
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Originally Posted by Helmwurst
(Post 4832048)
As you make adjustment to the mixture screws, give it a few seconds to find the new setting, then adjust the idle speed screw (throttle plate) to the recommended idle speed, usually around 700-800 RPM in gear. Repeat until motor is happy with vacuum and idle.
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Originally Posted by Zole
(Post 4832060)
great tip...but what shuld be my starting point..i know they cant be fully closed..screw in just enough so the engine can run or somthing difrent
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Might be a problem with ignition system.
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Originally Posted by TexomaPowerboater
(Post 4832086)
Might be a problem with ignition system.
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Originally Posted by Wally
(Post 4832088)
That is true....once had a problem where the engine idles great in neutral but always died when i put it into gear. Spent countless hours swapping parts. Turned out it was an advance spring inside the distributor that broke!
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Is it an alpha or bravo drive? Alpha uses a shift interrupter that interrupts the ignition.
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Originally Posted by liberator221
(Post 4832107)
Is it an alpha or bravo drive? Alpha uses a shift interrupter that interrupts the ignition.
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Originally Posted by 1BIGJIM
(Post 4832123)
That has nothing to do with idle.
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Originally Posted by Wally
(Post 4831973)
Ive done that buy just dropping the boat into the water still tied down to the trailer during the week when there is no traffic at the ramps to deal with.....
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If your idle mixture screws aren't having any affect, you have other issues. I would pull the carb apart and give it a good cleaning. You probably have buildup in the carb blocking the fuel path.
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Originally Posted by ThisIsLivin
(Post 4832348)
If your idle mixture screws aren't having any affect, you have other issues. I would pull the carb apart and give it a good cleaning. You probably have buildup in the carb blocking the fuel path.
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Check and adjust timing first, then follow this quote if mine before taking carb apart again, if easier for you then removing/taking apart.
Originally Posted by SB
(Post 4801811)
Grab a aerosol can of carb clean. Make sure you use red straw and blast both ways thru the top air bleeds 4 per side. 2 are idle and 2 are high speed. Some miss this for some reason. Watch your eyes, carb cleaner will squirt back at you. Remove idke mixture screws and spray thru that direction. Carb clean will come out bleed hole on top in carb choke tower right st your eyes. Watch out. Ive squirted my eyes hundreds of times and it hurts bad. Some water in them and just few minutes latet feel fine. I’d take out contacts if you have them.
Best way go set idle mixture screws are in the water, engine fully warned, and in gear. Typically best idle in neutral will need screws opened (counter clockwise) another 1/8-1/4 turn. |
If you have to pull carb, do it this way:
Originally Posted by SB
(Post 4801811)
Grab a aerosol can of carb clean. Make sure you use red straw and blast both ways thru the top air bleeds 4 per side. 2 are idle and 2 are high speed. Some miss this for some reason. Watch your eyes, carb cleaner will squirt back at you. Compressed air after doing this is better. As after spraying thru (both ways) all holes in metering blocks and bodies.
Best way go set idle mixture screws are in the water, engine fully warned, and in gear. Typically best idle in neutral will need screws opened (counter clockwise) another 1/8-1/4 turn. |
Originally Posted by SB
(Post 4832353)
If you have to pull carb, do it this way:
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Originally Posted by Zole
(Post 4832349)
allso..this carb has lower vacum reading then the other one
Bear in mind that once you have established optimal (or max) vacuum reading on a healthy engine there's other things that contribute to that reading besides the carb. You can have a flawless carb setup but if your timing is off , for example , your readings will be lower. I once had a Ford 351 with a full time vacuum gauge and if I started seeing the idle vacuum fall the first thing I would check would be the wear on the heel of the points mechanism. Re-set points and back to full vacuum again . And BTW , I had a friend visit Croatia before the pandemic and the photos blew me away. What an incredibly beautiful and history laden place. . |
Hi guys im back...so this is what happend..i took the carb cleaner and blow the idle mix screws..started the engine no change...then i figured aut that one cilinder is not working...took the spark plug aut and change it...then things started getting better so i wanted to check aut other spark plugs...the head on the right side has long spark plugs and the head on the left side has short spark plugs..does that make a difrence..thanks..allso there was some back fire from the carb but stoped after a wile
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There are some shorter plugs than others. Most important thing is that they working correctly (not fouled or worn) and of the proper type for application. Post both part #’s please.
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Sorry im on my other work place...ok
https://cimg2.ibsrv.net/gimg/www.off...7c789ebb07.jpg This is my work place...american engines are my hobby |
Allso i noticed that when i turn the distributer the engine won't pick up rpm...ill have to check my timing but the problem is thet ewerithing is rosted and i can't see advance....i only see three litle teeth and a big one...and 0 on my crank pully
https://cimg0.ibsrv.net/gimg/www.off...e486b5db97.jpg My boat https://cimg8.ibsrv.net/gimg/www.off...e0cffcd115.jpg My boat |
If your timing tab looks exactly like this, thrse are the btdc #’s vs indentions
Don’t pay attention to that 6 poiting at timing tab. That’s a reference to just the timing tab itself for that page in the manual. https://cimg0.ibsrv.net/gimg/www.off...859032193.jpeg |
Yes that is it...the big gap is 0 so i put mine betwene 8-12...but i felt it when rpm started to raise...the other engine does not have that but it von't response when i turn the distributer...no rpm raise
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Hy crew...can sombody tell me what are the proper spark plugs heat value for mercruiser 7.4 n/a
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MR43T for most of them. So, #43’s for acdelco plugs. If using NGK plugs, many people use #6 heat range.
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SB you are the best:ernaehrung004:we youse ngk...ill look at it tomorow...we run on 95 oktane fuell..does that make a differenc
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just run 87 if you have it no need for 95, use the extra cash for beer...........:D
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Originally Posted by F-2 Speedy
(Post 4833211)
just run 87 if you have it no need for 95, use the extra cash for beer...........:D
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Fuel
We don’t measure fuel # the same in Europe as in US. US87 (Mon) and Euro95 (Ron) are nearly the same. Ron, Mon, Pon,
In Europe we usually measure in Ron and in US you measure in Mon. //Peter |
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