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Pro tech to distributor conversion

Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=49881
Printed Date: April-25-2024 at 9:57am


Topic: Pro tech to distributor conversion
Posted By: Nautiquehunter
Subject: Pro tech to distributor conversion
Date Posted: June-08-2021 at 7:33am
A friend of mine bought a PCM# RK107025A  conversion kit from Nautique Parts. He asked if I could install it for him . It seemed pretty straight forward so I said yes . I thought the kit was made for this conversion but it is more like a bunch of cobbled up parts that are close but not quite a perfect fit to his engine. The directions are a joke hand written and very generic. He also supplied me with a copy of a wiring diagram for this kit off the forum . Using both and the knowledge I have from 40 years of working on 351 PCM engines I got it done . The boat runs great but I have a couple quirks . First the volt gauge reads low around 12 volts but 14.2 at the battery. Second the tach reads low about 4-500 RPMS it increases with the throttle but is off. The owner thought he has a ground issue in the dash that causes the volts to read low but the tach was reading fine before the conversion . Has anyone installed this kit and had similar issues? Any ideas where to start the gray wire is securely attached to the - side of the coil  ,





Replies:
Posted By: KENO
Date Posted: June-08-2021 at 8:03am
Another glowing review of the PCM "kit" Wink

Kinda reminds me of this recent thread

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=49747&KW=&title=removing-protec-throttlebody-installing-carb" rel="nofollow - link

Have you looked at the 8 plug connector at the back of the engine?

Maybe it needs cleaning since the power to the dash and the tach wire both go through there.

What's the voltage at the voltmeter if you check it with your VOM?

What's the voltage at the ignition switch BAT terminal when the engine is running. Is it low like the voltmeter or the same 14.2 as the battery?

Try the tach on one of your boats?






Posted By: GottaSki
Date Posted: June-08-2021 at 8:17am
I suggest while running, first check all hots from the buss and keyswitch out to harness to iginition and choke, against battery ground and find where the drop is, and address.


Then similarly check all grounds and see if any grounds are pulled up,  and fix those


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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."

River Rat to Mole


Posted By: Morfoot
Date Posted: June-08-2021 at 8:48am
Guess I missed the Conversion Party this weekend. Sorry I wasn't there to add another DOT worker to the mix. Hopefully Jim was pleased with the conversion. We all know the slightest bit of corrosion or dirty ground can cause issues. The 93 is always open to the elements with a cover on it so I agree with Keno and Ski. 

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"Morfoot; He can ski. He can wakeboard.He can cook chicken.He can create his own self-named beverage, & can also apparently fly. A man of many talents."72 Mustang "Kermit",88 SN Miss Scarlett, 99 SN "Sherman"


Posted By: 8122pbrainard
Date Posted: June-08-2021 at 8:58am
Mike,
As mentioned, get that VOM out and reort back to what you ind..




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64 X55 Dunphy

Keep it original, Pete
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Posted By: Nautiquehunter
Date Posted: June-09-2021 at 7:32am
After thinking about it I wonder if the tach is set to 4 cyl instead of 8 . The ProTech DI system fires both the compression and exhaust of two cylinder mates . That is why there are 4 coils on a V8 system. I will check this weekend . Has anyone else installed this kit and had this trouble? I am working on a 93 Sport 351 w.


Posted By: KENO
Date Posted: June-09-2021 at 8:20am
An 8 cylinder engine with the tach set on 4 cylinders will read double the actual RPM.

If it's at 1000 rpm and you set the switch to 4 cyl, it'll read 2000rpm

It'll always be off by a factor of 2 at whatever speed you're running the engine, not a 500 rpm difference like you're talking about.




Posted By: Laurieirving
Date Posted: June-10-2021 at 3:00pm
I have just received the exact same kit sent to me in Scotland. I can sense this is going to be fun converting it all 😭.



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