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'73 Silverton w/Chrysler 318 Speed/load issues

Not right. Peak horsepower is around 4000 rpms. There is something holding you back.

Most common are:
To much pitch in your propeller
Prop shaft misalignment
Timing issue
Carb issue
low compression
worn cam lobes
water logged boat
heavy marine growth on bottom
 
jp253 said:
'73 silverton fiberglass 7k weight with single 318 10.5 ft beam. Is 17knots at 3100 rpm normal or not right?
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Are you maxing out at 3100 or asking if 17 knots is normal at 3100?

17 knots sounds reasonable at that engine speed, but she should have a bit moreto at WOT.

-JJ
 
Tahoerover said:
Not right. Peak horsepower is around 4000 rpms. There is something holding you back.

Timing issue
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Mr. Tahoerover, I'm messing with JJ, but just what would expect a timing issue to be?
Shouldn't we just set BASE, and button it up?

Oh come on.... have some fun with me on this one! :D I'm just kidding JJ.


.
 
most likely prop is good
new carbs
tune up full
compression good
fuel good
timing good but double check this week however i did have it checked manully while underway and it was good at its current point
 
jp253 said:
tune up full
/QUOTE]
I think your full tune missed something:
attachment.php
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JJDebeers said:
Are you maxing out at 3100 or asking if 17 knots is normal at 3100?

-JJ
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I have to agree with JJ. The numbers do not mean much to us unless we know if the 3,100 IS or IS NOT the WOT RPM.
If 3,100 is the WOT number, then sometime is holding it back.

JP253, what would prevent you from strobing your timing marks, and seeing if the ignition is offering a progressive advance?
 
RicardoMarine said:
I have to agree with JJ. The numbers do not mean much to us unless we know if the 3,100 IS or IS NOT the WOT RPM.
If 3,100 is the WOT number, then sometime is holding it back.

JP253, what would prevent you from strobing your timing marks, and seeing if the ignition is offering a progressive advance?
Click to expand...

Timing checking again tmmrw since work on dist. 3100 is max
 
jp253 said:
Timing checking again tmmrw since work on dist. 3100 is max
Click to expand...
OK... if 3.1K RPM is MAX, you are below specs, although I don't know what your OEM specs are..... but that has to be low.

I think that you need to perform a fresh WOT RPM check.
Fresh WOT RPM check requires:

  • Hull clean
  • Prop in full tune
  • Over-all final drive ratio correct for the engine
  • Fuel delivery system fully up to parr... **I mean everything.
  • Engine in full tune... including progressive advance and TA ignition timing
  • Compresssion readings up to snuff
  • Yada yada yada..... you get the point

Only then can we perform a WOT RPM check that is worth a hoot.



** pick up tube, anti-siphon vavle, filters, fuel pump, carburetor, and so on.
 
jp253 said:
boat is running better after replacing both dist weight springs. anyone know if the both springs should be the same?
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Be very careful when changing flyweight return springs without knowing precisely what you are doing.

Yes.... each flyweight return spring is of a different value, and since you did not know this, I'll suggest that you read these threads.


http://www.marineengine.com/boat-forum/showthread.php?400801-Timing-a-318


http://www.marineengine.com/boat-forum/showthread.php?401023-Timing-and-max-RPMs-for-a-360
 
I did not locate anything specific discussing spring replacement in the Mechanical advance. They were shot so I had no choice. But they are the same springs made for a malory dist.



RicardoMarine said:
Be very careful when changing flyweight return springs without knowing precisely what you are doing.

Yes.... each flyweight return spring is of a different value, and since you did not know this, I'll suggest that you read these threads.


http://www.marineengine.com/boat-forum/showthread.php?400801-Timing-a-318


http://www.marineengine.com/boat-forum/showthread.php?401023-Timing-and-max-RPMs-for-a-360
Click to expand...
 
jp253 said:
I did not locate anything specific discussing spring replacement in the Mechanical advance. They were shot so I had no choice. But they are the same springs made for a malory dist.
Click to expand...
I understand that you need to replace these, but as I said..... Be very careful when changing flyweight return springs without knowing precisely what you are doing.

The flyweight system operates centrifugally and within a fairly small radius and operates at 1/2 crankshaft speed.
The final spring value, and the spring's influence on the flyweight system curve, is very critical that it be near dead on.
A 1 degree error at the distributor, is a 2 degree error at the crankshaft.
A 3 degree error ends up being a 6 degree crankshaft error, bla bla bla.... you get the point!



A lazy or mildly aggressive curve/limit will not damage an engine.... it will simply hold back performance.
However, an overly aggressive curve/limit may cause damage, and the spring rate/value has complete control of your advance curve/limit.

Please read the threads that I linked you to earlier. These should help explain why this is so important.
I'm trying to scare you just enough to cause alarm.
You do not want to end up with something like this:
piston_detonate1.gif


or this:
DetonationFailure01.JPG
 
[b


I have looked at an actual Chrysler book, several repair shops and speed shops.
No one has a clue about what springs to use..




iQUOTE=RicardoMarine;395302]I understand that you need to replace these, but as I said..... Be very careful when changing flyweight return springs without knowing precisely what you are doing.

The flyweight system operates centrifugally and within a fairly small radius and operates at 1/2 crankshaft speed.
The final spring value, and the spring's influence on the flyweight system curve, is very critical that it be near dead on.
A 1 degree error at the distributor, is a 2 degree error at the crankshaft.
A 3 degree error ends up being a 6 degree crankshaft error, bla bla bla.... you get the point!



A lazy or mildly aggressive curve/limit will not damage an engine.... it will simply hold back performance.
However, an overly aggressive curve/limit may cause damage, and the spring rate/value has complete control of your advance curve/limit.

Please read the threads that I linked you to earlier. These should help explain why this is so important.
I'm trying to scare you just enough to cause alarm.
You do not want to end up with something like this:
piston_detonate1.gif


or this:
DetonationFailure01.JPG
[/QUOTE]
 
jp253 said:
I have looked at an actual Chrysler book, several repair shops and speed shops.
No one has a clue about what springs to use..
Click to expand...
I know..... we've been trying to find the Chrysler Marine specs for some time now. I've been doing the same with every Chrysler Marine work shop manual PDF file that has been posted.
We can find BASE advance info all day/week long..... but we continue to come up empty handed regarding a curve/limit.

And with zero specs, no one with a distributor machine will be able to truly set one up for you/us.

One of the guys suggests a curve/limit that you may conisder, but you're on your own with this.
IMO, the curve could be rather linear, and a full in TA should be no sooner than let's say 3k rpm.
Since cruising RPM is rarely beneath 3k rpm, I think that this would be safe.

I'm sure that we'll keep looking, but I don't have any high hopes of finding the OEM info for the Chrysler Marine engines.
Apparently they put all of their trust in the OEM distributor advancing system, and with no concerns of what may occur down the road! :mad:


.
 
ok so i finallly found a speed shop guy with knowledge on this dist and the advance springs. he should be able to get me going however there is still the issue of base timing and how to set the springs as both will be at different tensions
 
so i couldnt talk to the speed shop guy today but according to mallory thedistributer i have isnt made by them so back to square one. anyine have a clue what dist this is attached..


IMAG1039.jpgIMAG0986.jpg
 
Which actually owns Mallory. When reading the fine print on the Mallory distributor box this weekend i saw that Mallory is a Prestolite company.-JJ
 
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