Fuel Filter questions for Older Mercruiser I-6

[RotaryRacer]

I have a 1981 Mercruiser (Chevy) Inline-6 165 HP mated to a pre-alpha drive. Not that it matters but these are in/on a 4Winns boat.

I don't have serial numbers in front of me right now.

Is there a fuel filter right in the fuel pump housing attached to the side of the motor? I am pretty sure there is but would like confirmation.

I have a purchased a navman fuel flow transducer, along with a chartplotter. The literature strongly encourages installing a fuel filter before the transducer.

I have temporarily installed one of the cheap ($7) in-line plastic housed filters that you can get at any marine store. The package had a warning on it about only being used on outboard motors. I thought that was a little odd and couldn't really figure out why it would be a problem on an I/O. I have not intention of using this full time. It was simply installed for testing purposes.

On the first outing to test out the fuel computer and some other things I noticed a slight mis at top end that I didn't remeber hearing before. I am concerned that it is running a bit lean due to the additional flow restriction of the filter.

Why are those filters labeled for outboard use only?

Would a good water seperating filter cause any noticeable flow restriction?

Thanks.

 

[ziggy]

Re: Fuel Filter questions for Older Mercruiser I-6

if it's the carter low or high volumn fuel pump. there is a filter in the fuel pump. in the can under the bail. there is also a screen type filter at the inlet to the carb. if you wish, a water seperateing fuel filter can to be installed between the fuel tank and the fuel pump. myself, i have no water seperating fuel filter. i'd guess the recomendation would be to have one though....

 

[Bondo]

Re: Fuel Filter questions for Older Mercruiser I-6

Would a good water seperating filter cause any noticeable flow restriction?

Ayuh,...... They don't any restriction,...... Unless there's a Reason........

I believe a good spin on canister type should do what you want,.....

 

[Fishermark]

Re: Fuel Filter questions for Older Mercruiser I-6

The reason is a safety issue. If the filter breaks and / or leaks fuel, the fumes will collect in the bilge and can cause an explosion.

No such worry on an outboard.

That's why you need to use marine parts on an I/O - things like the alternator, starter, etc - even the fuel lines themselves. The fuel lines need to pass fire tests, etc.

 

[RotaryRacer]

Re: Fuel Filter questions for Older Mercruiser I-6

The reason is a safety issue. If the filter breaks and / or leaks fuel, the fumes will collect in the bilge and can cause an explosion.

I figured that was the reason. I guess that is why I decided it would be fine for temporary use. I was keeping a close eye on to make sure there were no leaks.

if it's the carter low or high volumn fuel pump. there is a filter in the fuel pump. in the can under the bail. there is also a screen type filter at the inlet to the carb. if you wish, a water seperateing fuel filter can to be installed between the fuel tank and the fuel pump. myself, i have no water seperating fuel filter. i'd guess the recomendation would be to have one though....

I'm sure it is the standard fuel pump. I think it matches your description. Thanks for confirming it for me.

Ayuh,...... They don't any restriction,...... Unless there's a Reason........

I believe a good spin on canister type should do what you want,.....

What concerns me is that the in-line filter that I got was the type that has clear sides. i figured it would be full of gas when the engine was running. It is laying basically horizontal and there is only gas about a quarter of the way up on the inside. The engine ran fine. However, the idle was a little high and there was a slight miss at WOT....I was thinking maybe it was a bit lean due to a lack of fuel.

Thanks for the input.

 

[Viking77]

Re: Fuel Filter questions for Older Mercruiser I-6

The reason is a safety issue. If the filter breaks and / or leaks fuel, the fumes will collect in the bilge and can cause an explosion.

No such worry on an outboard.

That's why you need to use marine parts on an I/O - things like the alternator, starter, etc - even the fuel lines themselves. The fuel lines need to pass fire tests, etc.

I am new to this Iboats Mercruiser web site. I am not sure how to post a thread. I use to own a 21' Centurion - 454 with a Panther Jet and I am thinking about getting a Viking with a 165 HP I/O Mercruiser. I believe that it is best like you were saying to use Marine Quality parts that are fire tested. Any recommendations before I buy this Viking 165 HP I/O. THANKS

 

[Viking77]

Re: Fuel Filter questions for Older Mercruiser I-6

I am new to this Iboats Mercruiser web site. I am not sure how to post a thread. I use to own a 21' Centurion - 454 with a Panther Jet and I am thinking about getting a Viking with a 165 HP I/O Mercruiser. I believe that it is best like you were saying to use Marine Quality parts that are fire tested. Any recommendations before I buy this Viking 165 HP I/O. THANKS

 

[ziggy]

Re: Fuel Filter questions for Older Mercruiser I-6

v77, yer doing fine at posting. ya just need to start yer own thread to ask yer question. no one knows to look at this thread since it reguards fuel filters. anyways. any boat can be a good boat or bad boat. depends on how it was cared for. the L6 engine has been proven over time to be a very worthwhile engine to have. only thing about an L6 is that there won't be any mods to do to it period. there just is no aftermarket hop up parts available.... that said. a well tuned mercruiser 165 L6 engine is most desireable......imho........
ps, welcome to iboats. this is the place to be to get educated on yer boat. that's for sure....

 

[Viking77]

Re: Fuel Filter questions for Older Mercruiser I-6

Thank you Ziggy!

Do you have any Pics on your L6 boat and engine. I would like to see it.

Is the timing on the L6 250 6 deg. B.T.D.C.?

Thanks,