1989 85HP recirculation system

[DudeAbides]

Hello All. I am the proud new owner of an old 89 16' bayliner with its original 85HP Force.

I have read through a lot of the previous posts over the last 2 weeks and feel very lucky to have found this forum.

Thank you to all who contribute their time and knowledge here.

The issue I have been chasing is a rough idle and difficulty starting cold. Once I am in gear and opening up the throttle it seems to operate better.

I have gone through and cleaned the carbs (there was what appeared to be tiny bits of fuel hose in the bowls)

I am running fresh clean gas, my choke works well, timing is good.

​So I am now replacing all the original fuel lines including the recirc. lines

Does anyone have any guidance for cleaning the rest of the recirc system? my seloc manual shows the line routings and fittings but it is clearly not my model.

Should the cylinder reed drain cover come off?

It appears that all of my barb fittings are just open pathways except for the lowest one that comes off the manifold by the carb. This one appears to be a metering device and was completely blocked and had tons of junk in the hose.

So if anyone has gone through theirs and can offer any guidance I would appreciate it.

Thanks
Jason

 

[SkiDad]

make sure you idle is 750 when in gear in the water (adjustment is at bottom of tower with flat head screw and lock nut) - set your fuel mixture to around 1 or 1/14 turns out from lightly seated - that will affect idle quality - there is a FAQ at the top that explains more.

 

[DudeAbides]

Thanks Ski Dad. Yes I did the idle speed and mixture already with limited success. I have seen advice to clean the recirc system, but just nothing very specific.

I am hoping that clearing the clog in the one fitting, clearing the junk out of the hose and ultimately replacing all the fuel lines will help.

Its just that If I should do more to clean or inspect this system before it all goes back together, I would love to know what that would be.

Thsnks Again

 

[SkiDad]

when you change mixture you have to re-adust your idle rpm. i have had luck with running mercury quickleen in my tank - maybe you just need to run 'er for a while too. Then clean the spark plugs again.

 

[DudeAbides]

Thanks SkiDad. I plan on using some sort of product to clean the tank.

I have bypassed the tank for now and am just running out of a portable tank. Once I get things running better I will try quickleen.

I am surprised that I cant find more info on the recirc system and how it functions, especially since I found it all clogged up.

It has a line going right to the back of the fuel pump. I am assuming this is a like a vacuum that redistributes unburned fuel back into the lines going to the carbs?

 

[Frank Acampora]

The bottom fitting off the intake manifold is indeed a metered orifice. The hose and fitting take carb spit back fuel/oil from the airbox and recycle it to the intake manifold. The orifice is metered so that if there is no oil in the bottom of the airbox it will not cause a significant air leak into the manifold. This hose and orifice is not, strictly speaking, necessary. It will not change engine performance and the engine can run without it--inside the cowl will just get oily.

During idle conditions, fuel will "puddle" in the bypass passages. If not addressed it will build up to the point where a slug of fuel will be blown into the cylinder and cause a misfire. The drain system takes this puddled fuel and recirculates it before it can build to troublesome proportions. Each cylinder has a reed closed drain with a small screen that passes fuel down the cover. The hose at the bottom of the cover directs fuel into the cylinder to be burned.On the bypass cover there is a fitting. This fitting has a small pipe connected to it that goes in just to the bypass port so fuel IS squirted directly into the cylinder.

The purpose of the recirc. system is to improve the idle. It does not do much at high speed because the engine is able to burn any excess fuel delivered to a cylinder and fuel does not really have a chance to puddle in the bypass. If it is clogged idle performance will suffer. Since it does take air from the crankcase, the holes are specific size so do not enlarge them.

 

[DudeAbides]

Wow. Thank you for that explanation Frank. Much more thorough than my manual. It sure seems that my system is clogged. I tend to get a few misfires while idling. I checked the timing which is good. It also runs pretty nicely at higher throttle levels.

Thanks again

 

[DudeAbides]

No Title

I just thought I would post a pic of what I found under my cylinder drain cover. It sure looks like little bits of fuel hose, I found the same stuff, just not as thick in the bowls of my carbs.

Can anyone confirm what this sludge is? Is this what ethanol does to old hoses. I am replacing all fuel lines at this juncture

 

[kalebsheridan]

No Title

I just thought I would post a pic of what I found under my cylinder drain cover. It sure looks like little bits of fuel hose, I found the same stuff, just not as thick in the bowls of my carbs.

Can anyone confirm what this sludge is? Is this what ethanol does to old hoses. I am replacing all fuel lines at this juncture

Hey did this fix your problem? I think I may be in the same boat, no pun intended.