4.3 low pressure fuel pump

Nordic One

Recruit
Joined
Aug 18, 2023
Messages
5
Hi guys,
New to the forum and i have a question regarding the fuel pump for a 1998 4.3 carburated mercruiser.
The original fuel pump finally gave out and i purchased two # 861155A3 generic fuel pumps on Amazon and the first one spun for less than 10 seconds when i applied 12v to it and the second one didn't even make a sound, i returned both and purchased a Carter P4389 after reading some more positive reviews ...
Also picked up some 3/8 fuel lines from NAPA and will be bending and flaring adequately so i can use metal fuel lines rather than barbed fittings with rubber hoses.Does anybody have any feedback or suggestions before i go back to the lake next week and start the installation.
By the way , an original Mercury fuel pump is $1100. dollars plus tax in Canada !

Thank you
Phil
 

Scott06

Admiral
Joined
Apr 20, 2014
Messages
6,440
Hi guys,
New to the forum and i have a question regarding the fuel pump for a 1998 4.3 carburated mercruiser.
The original fuel pump finally gave out and i purchased two # 861155A3 generic fuel pumps on Amazon and the first one spun for less than 10 seconds when i applied 12v to it and the second one didn't even make a sound, i returned both and purchased a Carter P4389 after reading some more positive reviews ...
Also picked up some 3/8 fuel lines from NAPA and will be bending and flaring adequately so i can use metal fuel lines rather than barbed fittings with rubber hoses.Does anybody have any feedback or suggestions before i go back to the lake next week and start the installation.
By the way , an original Mercury fuel pump is $1100. dollars plus tax in Canada !

Thank you
Phil
hoses like this are offered in a couple lengths might be easier than bending and flaring. They are the same stuff that VP and Merc use as OEM

 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,674
Aftermarket is a crapshoot but Carter makes OEM fuel pumps so it’s probably the safest bet if not buying Merc OEM.
This is why I like old school carbed engines with mechanical fuel pumps. A brand new Carter pump is $75-$80 and the best carb kit you can get is about $60.
 

cjray03

Cadet
Joined
Aug 6, 2023
Messages
24
I recently purchased a 1985 Blue Water with the 4.3l v6 Mercruiser. It had been sitting for about 5 years. The fuel pump was rotted to pieces and the Holley 4160 carb was gummed up. I replaced the pump with an Amazon one and rebuilt the carb with the Amazon kit. I was very uneasy about the Amazon carb kit because it didn't have the blue gaskets in it. It had all the gaskets needed, but they were all just normal gaskets.
The engine would not start and run unless it was with starting fluid. I bought the Holley rebuild kit and new diaphragm and it started, but would not run except at idle.
I teed in a fuel pressure gauge and found that the pump was only doing a little less than 4lbs and when I revved the engine it dropped to 0. Brand new fuel pump. Anyways, I ordered an electric pump and all is well. Pumps 5lbs at idle and about 6 or so revved up.
Long story short...beware Amazon pumps, even new they won't necessarily do the job.
 

Nordic One

Recruit
Joined
Aug 18, 2023
Messages
5
Yeah, that's the issue with Chinese Amazon knockoffs , that's why i purchased two, it's like 20 minutes to replace in case the first one failed.The Carter pump has the fittings running horizontally as compared to the Mercury pump running vertically, hopefully it will be better quality than the 861155A3 knockoffs.I spent a whole day calling all the boat repair shops and marinas in my area and nobody had a used OEM pump lying around.What's ironic is i liberally sprayed some PB Blaster in my original 98 pump and it started to work again , but at this point i wouldn't trust it.I'll update my Carter replacement with pictures after i'm done, although i'm going to purchase a backup just in case i get stranded somewhere on the lake.Thank you all for the advice !
 

Nordic One

Recruit
Joined
Aug 18, 2023
Messages
5
Going to try this ...
I also have a 4 ft length of metal fuel line that i can bend and flare accordingly !

Mercruiser fuel pump.jpg
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,292
those electric pumps are all I will use. long lasting and trouble free.
I`ll try to get a pic of my setup tomorrow. What carb do you have on it?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,570
Original pump is a Carter/airtex. About $80

Nothing wrong with the Carter universal in the pic (I have been using them for decades). Use 90 degree fittings and you probably won't need to do anything but tweek your existing lines

Nothing good comes from chineseum knockoffs from amazon.
 

Nordic One

Recruit
Joined
Aug 18, 2023
Messages
5
Hey guys,

To follow up on my fuel pump adventure, the Carter fuel pump i received from Amazon was DOA ... so , i left the appropriate review with pictures and the review was removed by Amazon !
I called the Carter tech line and the guy told me " who knows what happens to those pumps on the way from China " he then basically told me to return it and order another one.
Look carefully at the picture , the shaft for the pump is not even centered in the bore, the cap which has four vanes on it was rubbing on the sides and of course the thing wouldn't turn.The funniest part is the box says that they are 100% factory tested, they probably meant the box ...

So like the Carter genius told me , i'm going to order another one from Amazon once i get my refund and keep ordering until i get one that actually works ... al least i didn't waste $100 on the Sierra flexible fuel line, it cost me $8.00 for a 40 inch section of 3/8 fuel line which i cut, bent and flared accordingly.I'll keep you posted if i ever get a functioning fuel pump.


Carter fuel pump - 1.jpgCarter fuel pump - 2.jpg
 
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