Which fuel filter for 86 Mercruiser 3.0

[jadenjdawg]

Trying to find the right fuel filter for 86 Mercruiser 3.0. Serial Number is A676603. Looking it up, it shows an old style, which has the filter on top of the fuel pump. (35-49088Q 2) And it shows a new style, which has the filter on the bottom of the fuel pump? (35-8M0046752 ) Everything i read says use the first one, but mine is on the bottom, which would be the second. Just need somebody with some expertise to confirm.

 

[Fun Times]

Your engine serial number comes up as an 1986 140 Model number 01402006.

Looks like they started going to the new design right around 1983.

When I first started looking at service manual number 8 which showed the new pump in the down position I then realized your 140 engine model isn't listed in that manual but it is listed in manual #10 which shows both designs.

http://boatinfo.no/lib/mercruiser/manuals/mercruiser10.html#/230
http://boatinfo.no/lib/mercruiser/manuals/mercruiser8.html#/188

When looking for a new fuel pump, Some of the most important things to know is what pump design you have, hopefully know/find the flange number of the old pump and check the "clock" position of the inlet, outlet, and separator fitting (where applicable) in relation to the rocker arm as mentioned in the following example link, http://www.ebay.com/itm/Sierra-18-7...el-Pump-Carter-42725A3-861676A1-/281738508873

Many fuel pumps are used on similar engines. In order to identify the correct fuel pump for your application, you must check the "clock" position of the inlet, outlet, and separator fitting (where applicable) in relation to the rocker arm. View the product photos to make sure this fuel pump is correct. The orientation is looking at the bottom of the fuel pump (with filter holder) and with the rocker arm sticking up/out.

Take notice of the part numbers for the 140 engine model here, http://www.sterndrives.com/fuelpumps.html

^ But with that info and depending on where you shop for a new pump, you can still find old stock of the older part numbers like in the eBay link but it seems in 1986+ they started updated the pumps with the newer numbers which ended up with the numbers you posted above due to some issues over the years. http://forums.iboats.com/forum/engi...990349-mercruiser-fuel-pump-old-vs-new-design

I don't mean to confuse you, just giving some history of what seemed to have taken place. You just need to be sure what you have before ordering as the serial number doesn't "exactly" tell which one to buy.

If all this don't help maybe posting a photo of your pump will help out.

Good luck.

 

[jadenjdawg]

Man, you are incredible. I can't thank you guys enough for the help and expertise here. I am a guy that has been on the water my whole life, but usually on lakes that only allow 10 hp or less and even eletric only. But, through this forum, I can at least have a conversation and halfway understand what I am talking about.

Anyways, my pump is fine, i think. This old gal is thirty years old, and has a slight hesitation at about 1500 rpm's, then takes off. I am not sure when the last time the filter was replaced, so I am going to give that a try first. My filter is down-facing, so hopefully that means the new design? Is that the primary difference in the filters, one being top of the pump, and one being bottom? I think when I get a good week where I am not going to the lake, I am going to take the filter out and go from there.

Figures my motor fits in a funky category like that.

 

[Fun Times]

If your pump is facing down then go/work with that. It would be best to pre-open the filter housing to have a look at your filter design as there are two types. That should help ensure you are ordering the correct one.

Hope the hesitation is something simple like the filter.
Good luck.

 

[jadenjdawg]

Fun Times. I guess i wasn't paying attention. Took the boat out today, and i was wrong. I have the old style, low volume, with the filter on the top. Anyways, my sight tube appears to have shrunk, and wasn't connected to the pump at all. Is that a big deal? and can i replace it with regular tubing of the same diameter? Also, didn't have any hesitation, but twice at WOT i lost all power. The first time, i was able to start right back up and everything was normal. The second time was about ten minutes later at WOT. This time it did not restart. I checked all the lines and nothing stuck out, but I was sitting in the middle of the lake with two kids so I couldn't do much else. I started to hook up my trolling motor and the wife suggested i try one more time. I gave it a couple pumps of gas and started cranking. It took longer than normal, but it did eventually start. We ran for another hour, and everything appeared normal. I think it was a fuel issue? I wasn't smelling any gas as i was cranking? What is your opinion?