Anybody ever hear of this one?

bluebear57

Petty Officer 3rd Class
Joined
Mar 12, 2011
Messages
76
My 150 outboard after rebuild starts and idles great,but give it a little throttle it either sputters and dies or races up to 3000 rpms a the key must be turn d off to shut it down. I have checked all I know, don’t know what else to try
 

bluebear57

Petty Officer 3rd Class
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Mar 12, 2011
Messages
76
I put linkage back I thought exactly as it came off, then tried making adjustments according to the manual, but I must be missing something.really sucks when yrs ago when I first started rebuilding out boards I didn’t really know what I was doing and never had any issues,now lm older and can’t get anything right.once again thank you for your help I’ll keep trying. Thank you very much
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,119
Is that a v6? If so, idle pickup timing is when carbs are still closed but ready to open. The timing should be 0-9* ATDC. Max spark advance s/b 21* BTDC.

If you are rebuilding a motor, a factory service manual is a must, I would think.
 

bluebear57

Petty Officer 3rd Class
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Mar 12, 2011
Messages
76
Thank you for your responce
Hate to bother you again , but going over the sync and linkage again I discovered that the butterflies on the lowest carb was out of sync, only opened 3/4 on wot could this alone cause my issues?
 

bluebear57

Petty Officer 3rd Class
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Mar 12, 2011
Messages
76
Is that a v6? If so, idle pickup timing is when carbs are still closed but ready to open. The timing should be 0-9* ATDC. Max spark advance s/b 21* BTDC.

If you are rebuilding a motor, a factory service manual is a must, I would think.
Yes your right , impossible with out one , I’ve had one for yrs, but as I had a stroke my memory and eye sight not what used to be. Thank you for your help
 

bluebear57

Petty Officer 3rd Class
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Mar 12, 2011
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76
Yes your right , impossible with out one , I’ve had one for yrs, but as I had a stroke my memory and eye sight not what used to be. Thank you for your help
I didn’t change any of the linkage and timing adjustments, should be the same,but I did just discover bottom carb was out of adjustment,loose screw I didn’t see. Thanks again your help is deeply appreciated
 

bluebear57

Petty Officer 3rd Class
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Mar 12, 2011
Messages
76
Thank you guys for all your help, it is greatly appreciated,I never touched the carb linkage so I took for granted lt was fine , it moved freely and seemed alright, after tearing back into the motor this afternoon and Checking stator CSI packs and resetting the linkage I still had the same prob.then I just happened to use a flash light and noticed that even with throttle off the butterflies were open loosened the linkage and reset , seem to have solved the issue.I hope that you very much for your time and help
 

bluebear57

Petty Officer 3rd Class
Joined
Mar 12, 2011
Messages
76
Good, Let us know how it works out on the water.
That was the last problem,one of the butterflies was stuck and not working, the other things that went wrong like stator,rectifier , and cdi packs that all of a sudden went out I believe was due to my onboard charger going out, it shorted out 2 batteries before I found out it was bad. I Took it out last night ran great. only other issue temperature gauge ,at low-speed lt stays on peg,but as soon as you start to accelerate the temperature gauge goes all way up starts over to overload overheat,and it has new impeller new water jackets gaskets ,new everything I’m hoping it may just be the gauge, when you shut it down the temp gauge drops really fast,I also removed the thermostats to be on safe side. The water coming out of the telltale is very warm,but you can hold your fingers in it, thanks again sir for your help, if you have any ideas about temp please let me know Lonnie
 

Faztbullet

Supreme Mariner
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Mar 2, 2008
Messages
15,931
Motor will overheat with t-stats removed...install new ones or restrictor washers
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,785
My 150 outboard after rebuild starts and idles great,but give it a little throttle it either sputters and dies or races up to 3000 rpms a the key must be turn d off to shut it down. I have checked all I know, don’t know what else to try
You are lucky you could shut the engine down. Paraphrasing what Faztbullet said, one day I was in the driveway, on muffs, working on my linkage on a 90 hp 2 stroke looper and I got the timing too fast (somewhere in excess of 22* BTDC I guess) and the engine took off on its own (pre-ignition with 87 octane fuel I guess) and pegged my OEM Merc 7k RPM tach. Took me a minute or two to get over the shock and another one or two to try and figure out what happened and what to do. Key had no effect. Had to clamp the fuel line to shut it down. Really amazed that I did no damage as It ran just fine for the next 2 years I had it after I got the L-S set up properly...per the manual.
 
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