Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

[1979Merc]

On 1979 Merc V150 outboard.

I just ran new fuel lines, new bulb and was wondering if you could put an in-line aftermarket fuel filter just after the prime bulb?

I restore old jeeps and often put an in-line clear high flow fuel filter.

 

[Chris1956]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

That is the correct place. Make sure you use a 3/8" ID fuel filter, or the fuel flow will be too little.

 

[1979Merc]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

Thanks for the input.

When I say "after the prime bulb" I mean between the prime bulb and motor....is this the correct location? Don't want to cut the hose too many times.

Thanks again.

 

[MercGuy]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

I put my filter before the primer bulb.

My logic (or lack thereof) is that if the filter clogs, the amout of force trying to pull crud through the filter is limited by the suction of the bulb.

If the filter is mounted after the bulb, one can squeeze very hard to try and force fuel (and crud) through the filter.

It's a minor point to be sure, but I don't see any negatives to mounting before the bulb.

 

[j_martin]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

That engine needs 15 gph of fuel at WOT. I put a Racor 60 gpm filter before the primer bulb, and discarded the little filter on the engine.

Works great. Solved a lot of problems.

John

 

[MercGuy]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

John,

I'm interested to hear more about this. What problems were solved ?

I've often been suspicious of the little filter on the engine, but I've been reluctant to remove it as it is the only filter for the 2-stroke oil.

Thanks,

-Steve

 

[1979Merc]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

Thanks for your help.

I think I will follow MercGuy and put it prior to the bulb as your rationale makes sense to me.

Any type in particular? Maybe the local auto parts store will have one. The Racor one sounds a little hard to find.

 

[Scaaty]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

Right size for the hose (3/8ths), and Wally World has'em for a few bucks. Run one in my 125, zero problems. And will pass more gas than me after a good bowl of chile..
Want Racor (not nedeed), fine, but hand over at least $100

 

[MercGuy]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

I use a Fram G3 clear inline filter, but there are many others of that style, I just buy what ever is convienient and change once per year. I carry 2 or 3 spares in my tool box.

About 17 years ago one of these types of filters saved me untold trouble. I was taking an over night trip on the Ohio river, and I filled up at the last gas station before a long relatively unpopulated stretch of the river. Apparently I got a bunch of rust during that fill up and my engine stopped 1/2 hour later.

The first saving grace was that the extra filter trapped all the rust. The second great fortune was that I had 2 more filters with me. I clogged the 2nd filter, and when I put the 3rd one on I fished the other 2 out of the trash bag and tried to wash them in the river in case I would need them. The 3rd filter ended up lasting until I got to civilization.

I've never run w/o extra filters since.

 

[j_martin]

Re: Can you/will it hurt to put an in-line fuel filter just after the prime bulb?

Thanks for your help.

I think I will follow MercGuy and put it prior to the bulb as your rationale makes sense to me.

Any type in particular? Maybe the local auto parts store will have one. The Racor one sounds a little hard to find.

It was a saga for sure. When I bought the boat, the engine balked at WOT, and the seller immediately dropped the price 500 bucks.

I figured that the fuel pressure was dropping so I put a pressure gauge in to check it. Sure it was the fuel pressure, went to 0 when the engine balked.

Changed the little white filter, which is only a 100 micron screen, by the way.
Immediate help, for awhile.

Checked the fuel pump, found a warped valve. Helped some.

Checked the fuel tank. It looked good, but when I put the last couple gallons through a 5 micron filter funnel, it plugged it up with a white creamy substance. Cleaned out the fuel tank, and it helped. Still dropped pressure at full WOT.

Replaced the aftermarket line and bulb with a Mercury one. Helped some more.

Replaced the aftermarket plastic bayonet fuel connector with nothing. (went direct to the T). WALLA, full pressure all the time.

Backed up and removed the cheep little mercury filter and put in a RACOR 320R-RAC-01 filter. I understand it should have been an 02 filter. Difference is metal instead of plastic water bowl.

My thinking is this. To run this engine lean when it's going hard is to risk serious piston damage from overheat. I got the fuel flowing, now I want it to keep flowing. A bass boat can easily take in a bit of water through the tank vent, so a water seperating filter was the best bet. I also solved a vent fuel splashing problem with a RACOR vent check valve.

I would spend the bucks to get a RACOR filter. It is just head and shoulders above the competition, and that is why the race guys with a gazillion bucks in their engines all run them. They aren't hard to find on the internet. I bought mine on eBay. I don't think IBoats stocks RACOR, just the cheep Sierra substitute.

hope it helps
John