Mercruiser 165 Sniper EFI Install

[djs42]

Getting ready to install Holley Sniper EFI on a carbureted Mercruiser 165. I have purchased a CP Performance exhaust riser to allow proper fit of the O2 sensor. My question is where do I install the coolant sensor?

Also any other guidance to installation of EFI appreciated.

 

[nola mike]

I stand corrected

 

[alldodge]

Think your going to need to drill and tap for 1/4 NPT in thermostat housing or head next to housing

 

[Alumarine]

Is this the 6 cylinder motor?
There might be a NPT plug adjacent to the current temp sender that you can remove.

 

[achris]

Is the Holley Sniper EFI SAE-J1171 rated? If not, don't install it!

 

[nola mike]

Looks to be, I hadn't heard of marine bolt on efi before.
https://www.holley.com/products/marine_and_powersports/marine/sniper_efi_marine/

 

[Bt Doctur]

Dont think your going to see that much more for the $1200 or so to buy it. If this is the 4 cyl mercruiser bastard motor 200 hp is about your limit

 

[alldodge]

Holley has been making these for a long time and many have put them on go-fast boats. Have heard they have been trying to get them approved for a long time, looks like they made it

 

[nola mike]

I've seen the auto versions, have the marine been around as well? Don't recall ever seeing a single thread about them around here. Very curious about how they do. They're $900 on eBay. Might not cost too much more than buying a 4bbl intake and carb for my 4.3 build. Don't know that you'd gain too much aside from the gee whiz factor with a tbi though.

 

[achris]

I've seen the auto versions, have the marine been around as well? Don't recall ever seeing a single thread about them around here. Very curious about how they do. They're $900 on eBay. Might not cost too much more than buying a 4bbl intake and carb for my 4.3 build. Don't know that you'd gain too much aside from the gee whiz factor with a tbi though.

Getting rid of the dribbly carb would be good enough reason for me... My old 4.3LX was a pain for that...

Chris....

 

[Scott Danforth]

The main unit looks to be SAE J1171 compliant, however not sure if its certified.

I do believe there is a compliance issue with the in-line fuel pump as the master kits do not have the J1171 note, only the base kit with a note that the fuel system must be compliant

 

[Nfowler]

The main unit looks to be SAE J1171 compliant, however not sure if its certified.

I do believe there is a compliance issue with the in-line fuel pump as the master kits do not have the J1171 note, only the base kit with a note that the fuel system must be compliant

Read SAE J1171 Electric fuel pumps are required to be wired through the oil pressure switch to inhibit the key on prime feature. Meaning, Holley's fuel system needs only to be wired properly to be compliant. The pump itself is not the issue. I just finished installing the Q-jet replacement sniper on my 5.7 Alpha. Its a dream compared to tinkering with an old rochester. It has never run so smooth and quiet since I've owned it. Plus, cold start is effortless, hot start is equally consistent, no pump and pray with a boat full of friends and family. I couldn't be happier with the results.

 

[djs42]

Thanks for all the replies. I know that the Sniper was originally designed for the automotive market and has been selling so well there that resource availability to focus on marine applications are sparse. The build I'm looking at is for a neighbor of mine at the lake on a sweet old Carlson. From what I have researched so far I know that most of the canned tune profiles that come with the Sniper are targeted to automotive and some manual tweaking will be required. Trying to gather all the info and parts before getting into it .. don't want his boat dry for too long. Nfowler I'll be in contact for your experiences. A few folks with intimate knowledge of the hw/sw involved in this project and will share anything we discover with you as well.