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Old 07-10-2023 | 09:59 AM
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Im redoing alot in my boat and one of the things since I am doing a engine upgrade was I install an JS alternators marine 170amp alternator. MY question is this:

1. Batteries go into the 1,2,both, off switch
2. Out of the switch to the starter
3. 0/1 Ga wire from the single wire alt also goes to the starter

There is no fused protection there at all, I feel like between the stitch and the starter there should be a Heavy Duty breaker there or am I over thinking it?

Getting close to fire up. Wiring and a bunch of little items to check off the list which takes the most time.

Another question I am running a carb since the Holley EFI is on back order, it used to be an MPI mag injection system but with the carb 1/2 throttle on the stick is wide open on the carb. I assume there is no adjustment to change the ratio of the stick to the carb opening?

Last edited by Joeyboost; 07-10-2023 at 10:06 AM.
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Old 07-10-2023 | 11:36 AM
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Depending on what controls you have, there may be more connection points on the throttle arm to change the amount of throw.
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Old 07-10-2023 | 07:22 PM
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Weird. Many years back I did gen v 502mpi to carb conversion and did not have a throttle issue.where on carb linkage did you attach the cable ?
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Old 07-10-2023 | 08:51 PM
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In regards to circuit protection, I've never seen anything between the batt, batt switch and starter. Any device in that path would likely restrict current when starter is engaged.

Between the alt output and the starter, I have seen high current breakers (usually down by the starter) That's probably a good idea. If you've ever got a wrench up against the output terminal on the rear of alt and ground, it gets exciting real quick. Also if something goes south electrically inside the alt, a breaker would stop the carnage before it got completely out of hand.
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Old 07-11-2023 | 06:03 AM
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Originally Posted by zz28zz
In regards to circuit protection, I've never seen anything between the batt, batt switch and starter. Any device in that path would likely restrict current when starter is engaged.

Between the alt output and the starter, I have seen high current breakers (usually down by the starter) That's probably a good idea. If you've ever got a wrench up against the output terminal on the rear of alt and ground, it gets exciting real quick. Also if something goes south electrically inside the alt, a breaker would stop the carnage before it got completely out of hand.
Now that you mention it I think there is a non-resettable circuit breaker that goes on the starter lug, is there a better option or just reuse that?
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Old 07-11-2023 | 06:06 AM
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Originally Posted by SB
Weird. Many years back I did gen v 502mpi to carb conversion and did not have a throttle issue.where on carb linkage did you attach the cable ?
On the carb the throttle linkage attachment point only has one hole that fits the cable bolt properly its closer to the swivel point than the other attachment points but half way on the control opens all 4 butterfly's 100% Ill have to pull the controls and see if they have additional cable attachment points.
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Old 07-11-2023 | 08:13 PM
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Originally Posted by Joeyboost
Now that you mention it I think there is a non-resettable circuit breaker that goes on the starter lug, is there a better option or just reuse that?
Really depends on what the non-resettable breaker is rated for in amps. If its 95A or more, I'd probably try it the way it is. Unless your trying to charge multiple batts simultaneously, or have some serious stereo amps or anything else that draws a lot of current, I doubt you will ever flow more than 95A (just charging a serviceable batt and running normal elec loads).

Being that you have pretty decent access to the starter, if the breaker ever trips ( due to overloading it), you should be able to bypass it to get yourself back into port. Depending on the configuration of the wiring connectors, might be a good idea to have a custom jumper available in your tool bag if needed.

Prev owner of my boat lost a trim pump fuse a few miles out in the gulf. Once he got back in, he installed short wires and a insulated spade connector to bypass the fuse if needed. Same principle.


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Old 07-12-2023 | 04:20 AM
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Originally Posted by Joeyboost
On the carb the throttle linkage attachment point only has one hole that fits the cable bolt properly its closer to the swivel point than the other attachment points but half way on the control opens all 4 butterfly's 100% Ill have to pull the controls and see if they have additional cable attachment points.
You have to use a bushing in the large hole

Google "holley carb throttle linkage bushing"


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Old 07-12-2023 | 04:24 AM
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Originally Posted by Joeyboost
Now that you mention it I think there is a non-resettable circuit breaker that goes on the starter lug, is there a better option or just reuse that?
That is actually a fuse. Nothing wrong with keeping that however I would also keep a spare on board. Just make sure to attach the battery directly to the starter post and the wire to the alternator to the fuse.

The starter circuit itself is normally not fused or current limited.
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Old 07-12-2023 | 09:03 AM
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Originally Posted by Mbam
That is actually a fuse. Nothing wrong with keeping that however I would also keep a spare on board. Just make sure to attach the battery directly to the starter post and the wire to the alternator to the fuse.

The starter circuit itself is normally not fused or current limited.
Yep This is what was on it when I removed the engine and I see the alternator went through it but not the starter or main cable from the battery. I have a 170amp alt replacing the stock 60amp but that shouldn't matter right?

Dont mind the rusty SH*Tbox in the backround thats my sleeper street shocker HAHAHA She loves hellcats their delicious LOL
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