Merc 260 fit in Winns 190 Horizon bay?

djaymasa

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Joined
Jun 12, 2023
Messages
22
I have 2 options of fixing up our blown 4.3 omc in our Horizon 190.

I have an old family boat that hasn't ran for 10 years but is clean and looks good. Has a 5.0 in it, but will require us to pickup over 600 miles away. Also costs us 1500 for the boat.

There's a local boat that has a 260 in it, but needs intake or head work. Cheaper and local even.

Will the 260 fit? I know the horizons came with 4.3 or 5.0 option, but how will the 260 fit?
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,734
I have 2 options of fixing up our blown 4.3 omc in our Horizon 190.

I have an old family boat that hasn't ran for 10 years but is clean and looks good. Has a 5.0 in it, but will require us to pickup over 600 miles away. Also costs us 1500 for the boat.

There's a local boat that has a 260 in it, but needs intake or head work. Cheaper and local even.

Will the 260 fit? I know the horizons came with 4.3 or 5.0 option, but how will the 260 fit?
The GM 5.0 and 5.7 (merc 260) are the same size.
Whether there are other differences in years that would impact you I don't know
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,852
Are the front motor mounts in the right place for that V8? Is the deck cut enough to allow the V8 length?

Side clearance should be the same.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,679
Not sure about the 190 but in my 1988 Horizon the engine mounts are definitely big enough for the V8.
 

djaymasa

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Joined
Jun 12, 2023
Messages
22
Alright, so we were able to fit and transfer the entire setup for the 5.0 merc including the outdrive. The only changes we had to do was create the 2 forward engine mounts and move them up forward about 5 inches. The other thing we dealt with was the steering linkage reqd larger bolts for the 5.0, so we had to grind 2 bolts down to size. Easy.... final thing we managed was the 8 pin to 9 pin update.

Our issue now that the motor is fully in and setup is there's no spark to the plugs. We've replaced the distributor and several otber things, but no change. The last things we can think of is the coil, ignition module or the sensors somewhere. Any good place to start??
 

djaymasa

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Joined
Jun 12, 2023
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22
Man Overboard switch installed correctly ?
We didn't do anything with the wiring beside connecting the harness.

One update, the 8 to "10" pin(although only 9) update wasn't done. But all I can tell is the pin 4 from the 10 pin is not connecting, which is for the engine alarm. Is that an issue? Is there a proper way to connect the harness from the original 8 pin to the updated 10 pinm
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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49,574
Follow the Thunderbolt trouble shooting guide in the stickies
 

djaymasa

Cadet
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Jun 12, 2023
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22
So installed an HEI distributor and found that the coil had no power. We ran a wire from batt to coil + and are getting spark. But now we can't determine where the loss of power starts. We can see that the purple wire on the harness isnt getting volts....Checking the ignition switch shortly.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,574
Marine motors do not use vacuum advance. Also, the only SAE J1171 tested HEI distributor is Davis Unified Ignition
 

cyclops222

Lieutenant
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Mar 21, 2024
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1,307
Big difference between..... It will work and it will work AND be safe in the engine room with gasoline fumes to ignite.

Boats & airplanes are more dangerous than cars. ALWAYS
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,679
Chinese HEI? I’d rather have an old Prestolite marine points distributor!
 

matt167

Rear Admiral
Joined
Sep 27, 2012
Messages
4,151
Chinese HEI? I’d rather have an old Prestolite marine points distributor!
They actually work well. A lot of them are basically unbranded MSD distributors. Just not for boats
 

djaymasa

Cadet
Joined
Jun 12, 2023
Messages
22
Moving on at this point to other things then.

The boat has the 8 pin cannon plug. The donor motor has the 10 plug. We can seat them together but obviously 1 pin is not connected. Is there a decent way to fix that? Is it necessary to fix that? If I remember correctly it's pin 4 for engine alarm.
 
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