Drain system check valves 1992 88 SPL

[capezig]

If I'm seeing things right...I have two fuel drain lines coming from the intake manifold (front) side of the engine (one near the bottom and one mid-way up between the carbs) and going around, one each to the sides of the block. One lands under the starter solenoid on the port side and the other lands under an electrical terminal block on the starboard side. If I pull the hose off the fitting on the starboard side of the engine and manipulate it with a syringe, I can only suck some fuel through the hose, and can't push any alcohol back into the engine. Pulling the hose off the fitting on the port side I can initially suck some fuel through, and then easily push alcohol back into the manifold end of the hose...so the check valve is not checking at the lower fitting on the intake side of the engine...

So...if the drain system check valve is stuck open, could this affect the running of the engine? My issue is generally that after a lot of low speed puttering, the engine frequently shuts down when going into or hanging in Neutral, randomly, and starts right back up with a flick of the key.

I would appreciate confirmation from someone that knows that I have a bad check valve and this could be contributing to my slow/idle random stalling problem...

Fair Winds and Following Seas, Zig

 

[V153]

Re: Drain system check valves 1992 88 SPL

Not entirely sure what you're talking about. "Check Valves"? Can you post a pic?

 

[racerone]

Re: Drain system check valves 1992 88 SPL

These check valves have some affect on idle quality.-----But I would first do a compression test on this motor.

 

[capezig]

Re: Drain system check valves 1992 88 SPL

Racerone...I have been tinkering with this issue for a long time. Early on I did do a compression test, don't remember the numbers, but at the time they were all in spec by my book. If you are familiar with these little 'check valves', does it make any sense that one would be checking and the other would not. I caught a comment somewhere about a check valve failure messing with the vacuum between the cylinders... It seems like I could be drowning half the engine in fuel? Might explain my very bad fuel consumption too? She runs great 99% of the time.

 

[racerone]

Re: Drain system check valves 1992 88 SPL

These valves are very small -------------The hoses are very small and not much volume of air / liquid can go through them.----What is " very bad fuel consumption " to you ?------Have you checked the fuel pump diaphragm ? -----The 88 spl did not come with VRO as far as I know.------Check compression again.

 

[emdsapmgr]

Re: Drain system check valves 1992 88 SPL

The drain system you are referring to is the "recirculation system." Created a few years earlier in order to improve the long-term idling by removing excess fuel buildup by the reed valves. They are very small and don't have much affect on the engine when running, but might have an affect on long-term idling if one/both of the one-way nipple valves was plugged. You may just want to replace those two screw-in valves as a normal maint. procedure. It's also possible the idle setting is too low. Check it. Should idle between 650 and 700 rpm's when the boat is floating normally in the lake and it's shifted into forward gear. If the idle is too low, it may not be able to sustain the idle after a few minutes in gear-and it could just shut off.

 

[capezig]

Re: Drain system check valves 1992 88 SPL

emdsapmgr et al; to be honest, I have been running a parallel conversation on E-nation, and we are coming to basically the same conclusions in both places. Now I just have to find the other two of these little tiny suckers and check all four of them. I now know I have at least one stuck open, which is screwing up the balance between the cylinders, and letting fuel/oil run the wrong way from the crankcase back around to the intake side...back to tinkering...and buying some more parts...

 

[emdsapmgr]

Re: Drain system check valves 1992 88 SPL

Not sure just what the configuration of your intake manifold is...I have a 95 intake manifold in the basement. Has 4 nipples for the recirc system. Two under each carb. The seem to tee together, reducing to a single line each, going to the block. You would have to get your hands on a factory manual to really see the setup diagram for your year. This system is not shown in the parts diagrams.

 

[capezig]

Re: Drain system check valves 1992 88 SPL

Emdsapmgr: finally progress! I pulled the carbs off again last week, found all four of those silly little check valves, including the one that was stuck open. One of our local dealers had one in stock, slapped it in and put her back together. Thursday, we ran the boat a little for a local sailing practice and it was solid with no stalls. Yesterday we tended a regatta all day and it had a couple fits of stalling, between most of the day running just fine. During the day, I took the last available adjustment on the idle screw and it now idles in gear ahead at about 750, out of gear in the water at about 1500. Seems a little strange that we are cranked all the way in on the idle screw to just catch the required idle. Any thoughts? old Boston Whaler Montauk 17 w/ 1992 Evinrude 88.

 

[capezig]

Re: Drain system check valves 1992 88 SPL

emdsapmgr: still running better than it has since we bought the boat. I tried once touching the idle down, but the old girl really didn't like it. We have dosed the fuel/oil liberally with SeaFoam and she seems to run better each time out...knock on wood. Thank you for your help and patience with me.

 

[emdsapmgr]

Re: Drain system check valves 1992 88 SPL

You are making progress. Normally that engine should idle down to 650 rpm's under the following conditions: boat is floating normally in the lake and it's in forward gear. If the engine does not like to idle at that low an rpm, possible you may need to clean the carbs internally. If any fuel dries up inside the idle passages over time, that will adversely affect normal low idle. To keep it running, you've incr the idle to 750, when then can affect the neutral idle rpm's-higher that they should be. Those higher idles rpm's cause high clutch dog wear when when shifted into gear from 1500. You can't clean those passages unless you pull the carbs apart and use a carb cleaner (like a Gumout product) to dissolve dried fuel gel deposits.