In-line fuel filter

[Christo]

Hi everyone,

My boat has a 5.0 mercruiser mpi with a bravo 3, it’s been not wanting to start last few times I’ve been on it, turns over though. Marina mechanic came over and started it and said “just give it some throttle”, you shouldn’t have to throttle an mpi engine to start it, right? I’ve never had to do that before, had the boat for a year. Then when it started, it was reving. Also, the infamous beep every 2 minutes was happening, no reading on the smart craft though. I asked him to change the fuel filter, and of course 2 weeks later, he still hasn’t done it. So I got one myself, along with the water separator filter, my question is, are those filters easy to change? Also, the in-line filter looks like it has some white sealer stuff on the threads, what is that? Thanks for any help Not waiting for my slow af mechanic to do it.

 

[Lazy Daze]

Sounds like a failing IAC valve (google/search here for that - lots of info). Idle Air Control.

Filters are easy, but that's a subjective rating, of course. Teflon tape or pipe dope - dope is better. Avoid the first thread.

Do you have the drop-in fuel water separator? There's two in the canister. I would skip the in-line - I don't think that's your problem. The F/W seps are a good maintenance thing so go ahead and do those. But, if it's easier to install the in-line than return it, go for it.

 

[Christo]

By avoid the first thread, do you mean don’t put the pipe dope on it there? I will google the iac, I did wonder about that as well. Thanks for the info lazy

 

[Christo]

Just watched a you tube video, guys boat was doing the exact same thing as mine, he changed the iac valve, and problem was fixed, so I’ll be changing that when I can get ahold of the valve, thanks again lazy.

 

[Lazy Daze]

Avoid the first thread... Yes, that's to make sure none of the dope gets pushed into fuel line.

The key to knowing it's likely the IAC is that it starts with the throttle advanced. Hence the name, "idle" air control

Yer welcome!

 

[Christo]

Hi there, I’m going to change the iac valve tmrw, I have a gasket with it, there’s another piece under the valve, almost like an extender to make it higher, should I put a gasket between that and the engine as well? In pic I marked it with the yellow arrow. Also, should I use thread locker on the bolts of the valve, and do they need to be torqued? Videos online I’ve seen didn’t do either. Sorry to be so needy, lol.

 

[Christo]

And thanks for any input

 

[paulswagelock]

No thread lock, there is likely a torque spec but I have just used the 1/4 socket and feel method.
As gar as gaskets, I don’t remember one at the base of the spacer, but if you don’t separate it, no need to mess with it.
And if your mechanic ignored the 2 beep warning, and isn’t familiar with the most common failure (IACvalve) when a boat needs advanced throttle to start or run at idle, time for a new mechanic.

 

[Lazy Daze]

I agree with Paul... both paragraphs

Actually, if I put anything on those threads, I'd be putting a little Perfect Seal or at least a high quality grease on them.

 

[Christo]

I agree with you both, the mechanic is a shit, I don’t understand why the owners of the marina let this shit go, but they are out of state, need to get their numbers and let them know they are losing money…however, their loss is my gain, I’m a self doer if I can…thanks for the great advice guys

 

[Fill Ess]

No gasket on the bottom -- just the one in between. When you remove the bolts holding the valve in place (17) then that valve body (14) will come loose

 

[Christo]

Awesome Phil, thank you!

 

[Christo]

Update…got the iac valve on and motor runs great, idles without dying, no throttle needed!! Thanks for all the great input guys, what a great feeling fixing my boat myself! Soooo awesome

 

[Lazy Daze]

Good!

 

[techmitch]

Update…got the iac valve on and motor runs great, idles without dying, no throttle needed!! Thanks for all the great input guys, what a great feeling fixing my boat myself! Soooo awesome

Yep, CSR rocks! Well worth it's weight in Silver, Gold, or Platinum. Choice is yours.

 

[Christo]

It is Mitch! So much knowledge and fun on here, I love it!

 

[OpieTaylor]

Is their an inline filter for the 4.3L MPI?

I have only been changing the spin on F/W separator, and at my wits end. Changing them every other trip now. The boat runs terrible for the first 30-1 hour then runs like a champ.

I have siphoned the tank, and attached a vacuum hose to suck out every drop. 08 185 sport, 166 hours and am dealing with low power/hesitation/stalling for first 30 min to 1 hour each trip then she decides to run great. I have switched gas stations and run non ethanol, run premium, run regular, used Stabbil, iso heet.

Any help would be greatly appreciated.

I haven’t checked fuel pressure, from the schrader valve because when it does decide to run well it’s runs very well.

 

[Fill Ess]

Is their an inline filter for the 4.3L MPI?

I have only been changing the spin on F/W separator, and at my wits end.

If you follow the fuel line from the top of the tank to the separator that you've been changing, it should be between those two if you have one.

 

[Christo]

Here’s what mine looks like Opie

 

[Lazy Daze]

Is their an inline filter for the 4.3L MPI?

I have only been changing the spin on F/W separator, and at my wits end. Changing them every other trip now. The boat runs terrible for the first 30-1 hour then runs like a champ.

I have siphoned the tank, and attached a vacuum hose to suck out every drop. 08 185 sport, 166 hours and am dealing with low power/hesitation/stalling for first 30 min to 1 hour each trip then she decides to run great. I have switched gas stations and run non ethanol, run premium, run regular, used Stabbil, iso heet.

Any help would be greatly appreciated.

I haven’t checked fuel pressure, from the schrader valve because when it does decide to run well it’s runs very well.

A fuel filter typically doesn't fix itself and get better the more you use it. I don't recall if your model uses an inline filter, but it's super easy to look and see in your boat. It will probably take you less time to look than it did for you to write that post.

When you've changed the F/W separator, have you dumped it into a clear container to check the fuel quality?

Disconnect the fuel line at the F/W separator and connect it to a portable fuel tank. If there are no issues when running the engine, the problem is on the upstream side of the F/W separator. If there's still an issue, the problem is downstream. Doing this will help you narrow down the possiblities.