89 mid cabin tachometer flutter

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mrrudely
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89 mid cabin tachometer flutter

Post by mrrudely »

So a couple of months ago I changed the port engine distributor to a HEI from AAA marine.
All went well runs perfectly.
Did the same to the starboard engine last week.
Engine runs perfectly.
Problem is that the port engine tachometer now has a flutter when the starboard engine is running. (both engines running)
Starboard tach is fine, shut down starboard engine, port tach is fine.
Both engines had two wires to the positive of the old coils, port engine has a third wire.
Third wire connected or not no difference.

Anyone?
10 meter mid cabin
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prowlersfish
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Re: 89 mid cabin tachometer flutter

Post by prowlersfish »

Do you have a synchronizer? If so disconnect it and see what happens
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77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
mrrudely
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Re: 89 mid cabin tachometer flutter

Post by mrrudely »

no synchronizer
10 meter mid cabin
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prowlersfish
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Re: 89 mid cabin tachometer flutter

Post by prowlersfish »

I have been thinking about this and have not come up with anything. I keep thinking synchronizer. And you don't have one. I Had a lot of issues with the Flashing light ones crossing over. The only other thing I can think of that could be shared electrically is the batteries Make sure the switches are not on all.

I am assuming the engines are holding steady even though the tach(s) are not?
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
mrrudely
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Posts: 180
Joined: Sat Jun 08, 2019 11:52 am
Location: Marina Del Rey, CA

Re: 89 mid cabin tachometer flutter

Post by mrrudely »

prowlersfish

thanks for giving this some thought
the engines hold steady and there are no battery switches
I was at the boat yesterday and verified my original observations at the dock
however when we went out past the breakwater we found both tachometers were fluctuating erratictally

I am thinking of installing tachometer filters which seem to be common on HEI installations
10 meter mid cabin
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BobCT
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Location: New Haven CT

Re: 89 mid cabin tachometer flutter

Post by BobCT »

Mike,

For what it's worth, I installed the exact same distributors and on my 454's and the tachs worked fine. Off topic, I put together a new spare parts "kit" (Ignition module, etc.) for these distributors but sold the engines. $75 shipped and it's yours.

I also have a full set of Int'l gauges if you or anyone else is looking (but I don't think your tachs are bad).


Bob
1988 10m mid cabin
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prowlersfish
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Re: 89 mid cabin tachometer flutter

Post by prowlersfish »

mrrudely wrote: Tue Aug 09, 2022 11:33 am prowlersfish

thanks for giving this some thought
the engines hold steady and there are no battery switches
I was at the boat yesterday and verified my original observations at the dock
however when we went out past the breakwater we found both tachometers were fluctuating erratictally

I am thinking of installing tachometer filters which seem to be common on HEI installations
Sounds like a good idea let us know.
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
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