No run at 8* BTDC. Fine at 25* BTDC

My_Twain_4

Cadet
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Aug 13, 2010
Messages
7
Re: No run at 8* BTDC. Fine at 25* BTDC

Hey, thanks again.

Gonna go tear out dizzy and inspect closer. My final ditch effort before we go boating today. Even if I can't get it timed correctly, I can still get it close enough to go and putt around, get out to island and do some swimming.

You know, I can achieve a somewhat smooth idle. But since timing mark is so far off tab, it runs even worse at higher rpm's.

My wife, kids, and I all completed the Army Corps of Engineers Boaters Safety Course yesterday. And since my son is 12 years old, he can legally operate boat.

My plan: set idle timing by ear, smooth as possible. Get on water and bring up to normal operating temp. Remove doghouse, get on plain (roughly 3500rpm), then reset timing by ear. See if I can't get it to run a little better while at higher rpm's.

My thinking: Since I cannot get accurate base timing, engine must not be advancing far enough (or too far) at high rpm's. It worth a shot?

If not, we just idle around all day. Its what we had to do on last outing. Wasn't gonna push engine when it wasn't right. Could tell it was lacking power and timing was culprit.

Will post any and all results. Thanks again guys...
 

bruceb58

Supreme Mariner
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Mar 5, 2006
Messages
30,582
Re: No run at 8* BTDC. Fine at 25* BTDC

I wouldn't run any engine with timing set by ear unless you don't mind buying a new engine...your call though.
 

bruceb58

Supreme Mariner
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30,582
Re: No run at 8* BTDC. Fine at 25* BTDC

did you make sure that before you timed it with light that you bypass the shift switch. and jump the 2 white wires coming out of distributer.if you dont do that it wont time right. and you cant use a digital,adjustible,timing light. you must use the basic time light
There is no bypass switch or wires for a distributor with points.

You can also use and adjustable timing light for any type of ignition.

You need to get your facts straight.
 

potatoe

Petty Officer 3rd Class
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May 27, 2010
Messages
77
Re: No run at 8* BTDC. Fine at 25* BTDC

sorry about the mix up in ignitions, but the timing light info comes straight out of the mercruiser shop manual. it clearly states, (an adjustible timing light should not be used with mercruiser engines.) mercruiser has found considerable inaccuracies in such lights. it can cause power loss or engine,and/or piston damage. and that is a fact for electronic or points ignitions. i hope that is more clear for anyone to understand.
 

EddiePetty

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Re: No run at 8* BTDC. Fine at 25* BTDC

...... it clearly states, (an adjustible timing light should not be used with mercruiser engines.) mercruiser has found considerable inaccuracies in such lights.......

...I'd be REAL interested in exactly what MERCRUISER manual made that statement!!!!!
 

potatoe

Petty Officer 3rd Class
Joined
May 27, 2010
Messages
77
Re: No run at 8* BTDC. Fine at 25* BTDC

that would be the clymer mercruiser sterndrive shop manual 1964-1985 (also includes 1986-1987 tr and trs models) section 4, page 74. lower left hand of the page.
 

scutty83

Cadet
Joined
Apr 25, 2010
Messages
27
Re: No run at 8* BTDC. Fine at 25* BTDC

Should be able to hook up your vacuum guage where the pcv valve is plumbed. (Back of carb on bottom plate)
Also have you double checked the condition of your plugs and wires?
I had a bad plug that gave me alot of grief.
 

bruceb58

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Re: No run at 8* BTDC. Fine at 25* BTDC

that would be the clymer mercruiser sterndrive shop manual 1964-1985 (also includes 1986-1987 tr and trs models) section 4, page 74. lower left hand of the page.
The Clymer is not a Mercruiser manual. Its a poor excuse of an aftermarket manual. This may explain a few of the other things you are stating.
 

EddiePetty

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Re: No run at 8* BTDC. Fine at 25* BTDC

The Clymer is not a Mercruiser manual. Its a poor excuse of an aftermarket manual. This may explain a few of the other things you are stating.

Thank you Bruce58...ya' beat me to the punch.
 

antsmands

Seaman
Joined
Apr 24, 2007
Messages
58
Re: No run at 8* BTDC. Fine at 25* BTDC

Thanks.

You know a funny thing? Out of the 200 times Ive pulled dizzy, somehow hoping to get as it was, everytime, I look at that roll pin. Sure would be nice if it was as simple as that.

Who knows, maybe it is something simple. It kicking my ***** though.

Installed old points/condensers. Same thing. I kicking myself hard right now. Should of just left it alone and not messed with it in first place. It was doing this when I bought, had it fixed, now cant get it right.

Fk_it, I ordering the Pertronix conversion kit tonight. Even if it doesn't fix timing issue, I can at least eliminate one freaking headache getting rid of them points.

Sure would like to go boating tomorrow though. I still open for any info. Thanks again guys. All reply's are appreciated.

The Pertronix is worth the money! Got one on mine and it help a ton. A least you will eliminate the points as an issue and can troubleshoot from there. I am very interested in finding why it is drifting as I have no idea. Good Luck getting it sorted out.
 

fishrdan

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6,989
Re: No run at 8* BTDC. Fine at 25* BTDC

The Pertronix is worth the money!

So what does a Pertronix cost, $90-100?

You can buy a complete 3.0L EST marine ignition (distributor, coil, wires, etc.) for $200.......
 

potatoe

Petty Officer 3rd Class
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Messages
77
Re: No run at 8* BTDC. Fine at 25* BTDC

The Clymer is not a Mercruiser manual. Its a poor excuse of an aftermarket manual. This may explain a few of the other things you are stating.
what few other things that im stating is incorrect? please let me know. is this a fake manual? because its titled mercruiser with 600 pages of pictures and specs, info. what is aftermarket manual? wouldnt the company get a lawsuit and go out of buisness for false information? the book explains that Mercruiser has found considerable inaccuracies in such lights.not clymer. how bad is this manual? its what i have been using, and its all i have. so if its going to bring me problems, what is the correct manual to get?
 

Howard Sterndrive

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Messages
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Re: No run at 8* BTDC. Fine at 25* BTDC

what is aftermarket manual? wouldnt the company get a lawsuit and go out of buisness for false information?

An aftermarket manual is one not published by the company whose product repair is being described.

The "For Dummies" books are a huge industry of this type. "Windows for Dummies" is not published by Microsoft.

Clymer is a company that publishes low cost "how to" manuals for cars, motorcyles, boats, snowmobiles etc. etc.
Seloc, Haynes, Chilton are others. There were about a dozen... not many left.

Mercruiser manuals are available from Mercury marine's own publishing group.

I'm sure Clymer has been sued. Getting sued (and losing) doesn't immediately put a company out of business...

Aftermarket manuals are like aftermarket parts... they usually get the job done, but sometimes they are just not right, or of inferior quality

what is the correct manual to get?

the specific OEM manual from Mercury marine for your engine model is far superior to aftermarket. Mercury manuals are sold at all Mercury / Mercruiser dealers

Seloc and Clymer do have a place..... they cover many models and have some cool generic maintenance charts, and gear ratio charts that aren't found in the single model OEM manuals

A Jobber mechanic can't afford every manual ever published, so the generic Clymer and Seloc sometimes have to do.
 

bruceb58

Supreme Mariner
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Messages
30,582
Re: No run at 8* BTDC. Fine at 25* BTDC

what few other things that im stating is incorrect?
You are telling the OP to put his distributor in base timing mode by jumping two wires! He has points! And why would you need to bypass the neutral safety switch to time an engine?

did you make sure that before you timed it with light that you bypass the nutral saftey switch. and jump the 2 white wires coming out of distributer.if you dont do that it wont time right.
 

6meter

Chief Petty Officer
Joined
May 15, 2010
Messages
525
Re: No run at 8* BTDC. Fine at 25* BTDC

Just some FYI, pulling a dizzy out and rotating it a tooth or two does nothing. It can be rotated on the motor and accomplish the same thing. It really doesn't matter where it sits in the motor, you just have to rotate it or move the plug wires around. The only time I've seen it matter is when astetics come in play. It looks better squared up.
 

potatoe

Petty Officer 3rd Class
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Messages
77
Re: No run at 8* BTDC. Fine at 25* BTDC

You are telling the OP to put his distributor in base timing mode by jumping two wires! He has points! And why would you need to bypass the neutral safety switch to time an engine?

the shift interpeter switch is what needs to be unpluged and joined together at wire harness when timing est ignition. if this is false information then i dont know what to do. i dont make up anything i say. this is info that im gathering off this forum. and its been very helpful so far. is this true or false
 

Howard Sterndrive

Rear Admiral
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4,603
Re: No run at 8* BTDC. Fine at 25* BTDC

the shift interpeter switch is what needs to be unpluged and joined together at wire harness when timing est ignition. if this is false information then i dont know what to do. i dont make up anything i say. this is info that im gathering off this forum. and its been very helpful so far. is this true or false

first of all, if you mean shift interrupt switch, that is false

secondly, he does NOT have EST ignition.. he has breaker points
 

EddiePetty

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Re: No run at 8* BTDC. Fine at 25* BTDC

.....the shift interpeter switch is what needs to be unpluged and joined together at wire harness when timing est ignition....... is this true or false

...Quite FALSE !!!!! If you tie the interupter leads together, the engine won't start...NO SPARK !!!!

EDIT: Sorry Howard...you type faster than I do !!! :)
 

fishrdan

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Re: No run at 8* BTDC. Fine at 25* BTDC

the shift interpeter switch is what needs to be unpluged and joined together at wire harness when timing est ignition.


ARRRRGH!

This is getting quite confusing since the "EST" ignition is being talked about when the OP has points.

On an EST ignition you have to short the shift interrupt wires together "at the right time" to time the engine. This has to be done.

On a points ignition, shorting the shift interrupt switch wires will kill the ignition... Not way to time the engine if it won't even run.
 
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