Author Topic: Secondary Air Valve spring setting  (Read 263 times)

Offline rad1026

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Secondary Air Valve spring setting
« on: June 03, 2020, 02:02:45 PM »
On a marine carb.  Any suggestions on a good initial starting point for the spring adjustment? 

Offline Cliff Ruggles

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Re: Secondary Air Valve spring setting
« Reply #1 on: June 04, 2020, 04:00:22 AM »
I set them at 3/4 turns from when the spring just touches the pin.

This assumes you are using a new spring.  Old springs tend to loose their tension over the years and it becomes difficult if not near impossible to find a good setting for them.   Typically you have to wind them too tight to prevent some issues when the secondaries come in......Cliff

Offline rad1026

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Re: Secondary Air Valve spring setting
« Reply #2 on: June 04, 2020, 07:23:28 AM »
New spring from the kit you just sent me Cliff.  I replaced the secondary meter rod cam.  When I reattach the air flaps can I use locktite on the screws or should I stake them or both?

Offline tayto

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Re: Secondary Air Valve spring setting
« Reply #3 on: June 04, 2020, 11:45:09 AM »
i personally just loctite them incase i have to disassemble in the future

Offline rad1026

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Re: Secondary Air Valve spring setting
« Reply #4 on: June 05, 2020, 06:48:37 AM »
I went ahead and did both.  Kind of a pain to set up the stake though.  Could have used an extra set of hands but was able to position it on my vise and get a good solid punch.  I'm hoping I don't have to take it apart again. 

Offline Cliff Ruggles

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Re: Secondary Air Valve spring setting
« Reply #5 on: June 09, 2020, 03:37:12 AM »
I just use the red Loctite as it's a PITA to stake them without bending the shaft. 

Nothing wrong with "staking".  When I stake shaft screws I clamp a 1/2" aluminum punch in the shop vise and locate the screw head solidly on it then "peen" the screws with a tiny machinist hammer........Cliff

Offline rad1026

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Re: Secondary Air Valve spring setting
« Reply #6 on: June 29, 2020, 08:17:02 AM »
Got a chance to install and run the Carb this past week.  All I can say is Wow!

Two pumps of the throttle and one click of the key and she started right up and idled perfect.  Didn't really have to make any adjustments.  I got out past the no wake zone and hit the throttle to the floor and absolutely no hesitation, she jumped up and ran hard until I reached max RPM.  I had the idle screws set at 2.5 turns and thought about playing with that setting but after it warmed up it seemed so perfect I didn't touch it.  Idled at about 850 in gear, which is correct and about 700 out of gear.  I didn't touch it. 

Two things-

After running for a while and shutting down it took some cranking to get it started again.  It could be just a learning curve on my part.  I tried just turning the key, but maybe I need a couple squirts or to hold the throttle open while cranking.  That didn't happen every time either, several times after sitting for only a few minutes it started right up with just a turn of the key.  So again, maybe just a learning curve on my part.

The new bottom gasket is so thick the two front bolts barely caught threads.  I removed the washers in order to get them set but I will definitely need to get some longer bolts. 

Super happy with the rebuilt Cliff, thank you for the kit, the book and the advice in here.

Offline tayto

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Re: Secondary Air Valve spring setting
« Reply #7 on: June 29, 2020, 11:28:42 AM »
you should have to bearly touch the key and it should catch on hot start,no touching the gas pedal. might need some more initial timing. i've always set initial by getting the motor hot soaked, advance 2*,shutdown, wait for temp to spike (~5 minutes) and then try cranking. if it starts good repeat the process until it hard starts/windmills then back of timing 2*.

Offline Cliff Ruggles

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Re: Secondary Air Valve spring setting
« Reply #8 on: June 30, 2020, 03:10:46 AM »
I would purchase a piece of stainless steel 5/16" threaded rod and make studs for the carb.  That is what I do here in lieu of using bolts as it ensures maximum thread engagement in the intake manifold.....

Offline rad1026

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Re: Secondary Air Valve spring setting
« Reply #9 on: June 30, 2020, 07:32:25 AM »
Good advice Cliff, I will do that.

I haven't checked the timing in a while.  Its probably time I do.  Won't be back out to the old girl for a few weeks but I will look at the timing next time.