VRO elimination issue

[halmc]

No thread highjacker, me, I decided to ask this question in a new thread.

In a current thread <http://forums.iboats.com/showthread.php?t=242166> Joe Reeves offered a step by step plan for elimination of the VRO, which included this instruction:

1 - Cut and plug the oil line at the engine so that the oil side of the VRO pump will not draw air into its system. Trace the wires from the back of the VRO to its rubber plug (electrical plug) and disconnect it.

This really caught my eye because at some point in a '88 40 hp Evinrude's life I'm becoming aqainted with, the vro function has been eliminated. But I don't see any plugs.

In Joe's step #1, he says "cut and plug the oil line at the engine". Can either Joe or someone else be more specific about the 'oil line at the engine'.

I had my VRO off today. I noticed a quarter inch (ID) hose connecting to a fitting that runs directly into the base of the engine. I reasoned that this hose was the source of vacuum that powers the fuel pump . . . ? Is that the line Joe is talking about?

Since this engine is running as if it had a huge vacuum leak, I really got to get a handle on this issue because if that quarter inch line is sucking air in, I might be on top of my crappy running issue. Comments please!!!

 

[Joe Reeves]

Re: VRO elimination issue

The VRO pump has 3 connections on the bottom area and 1 on top of the VRO.

The top fitting obviously leads to the carburetors.

The forward bottom fitting leads to the crankcase (pressure/vacuum) and is the operating source of the pump.

The center bottom fitting is for the incoming gasoline source.

The smaller rear fitting is for the incoming oil source.

Exactly what is your engine doing that you suspect a huge vacuum leak?

 

[halmc]

Re: VRO elimination issue

Exactly what is your engine doing that you suspect a huge vacuum leak?

It will run like a banshee for about nine seconds after the enrichener is actuated, either manually, or with the key. Then it quits. If one actuates the "choke" just before it dies, it rips up (unloaded) to about 3k or so, then dies.

I have cleaned both carburetors, by disassembling each of them, removing all of the jets, "boiling" them in automotive carb cleaner.

It has huge blue, fat spark and will jump about 3/4" from the end of the high tension lead if given an opportunity to do so.

Both carbuetor bowls fill correctly, even so, pumping the fuel hose changes nothing.

Compression is adequate and even at ~135psi.

Today, just for the hell of it, I removed the entire fuel pump and VRO assembly and ran -- or attempted to run -- the engine. I connected the fuel line directly to the carburetor "manifold" (the little item that splits the fuel supply to each carb and to the enrichener) and kept the engine supplied with fuel manually. I of course plugged the remaining vacuum ports on the base of the engine. (I see two) Same symptoms.

I'm an experienced gearhead on motorcycles and autos, and even some marine stuff, but this one has me stumped. I don't even know whether I'm facing a ignition issue or fuel!

Woe is I.

 

[HighTrim]

Re: VRO elimination issue

Today, just for the hell of it, I removed the entire fuel pump and VRO assembly and ran -- or attempted to run -- the engine. I connected the fuel line directly to the carburetor "manifold" (the little item that splits the fuel supply to each carb and to the enrichener) and kept the engine supplied with fuel manually. Same symptoms.

Dont want to jump in here but I sure do hope that you ran a seperate tank with pre mixed fuel in it for this test.

 

[halmc]

Re: VRO elimination issue

Dont want to jump in here but I sure do hope that you ran a seperate tank with pre mixed fuel in it for this test.

By all means, jump right in. The engine was some time ago "converted" to premix, and I ran premix in it during the test.

When I read Joe's post, it occured to me that the DPO, when he or she did the conversion to premix, that they left a port into the crank case open such that it's gulping air in to the crankcase. Trouble is, of course, a two stroke engine creates both vacuum and pressure in the crankcase, so were that true, it would be blasting fuel/oil/air mixture all over the inside of the cowl and it isn't.

 

[Joe Reeves]

Re: VRO elimination issue

The enricher as you call it is actually a Fuel Primer Solenoid. The automatic (normal) position for the RED actuating lever is to be over top of the solenoid and pointing directly at the other end of the solenoid.

The fact that the problem still exists when you have the fuel lines connected directly to the carburetors, and apparently were pumping the fuel primer bulb (acting as a manual fuel pump), indicates that fuel is not flowing thru the carburetor assemblies.

The fact that when you actuate the fuel primer solenoid, which applies fuel directly to the intake manifold area, bypassing the carburetors, the engine responds as it should...... this allso indicates that fuel is not passing thru the carburetors.

In each carburetor, there is a fixed brass high speed jet in the bottom center of the carburetor float chamber. Fuel must absolutely flow thru those jets before it can flow to any other passageway in the carburetors. It is best to manually clean those jets with a piece of single strand wire as solvent simply doesn't do that job as perfectly as it should.

 

[halmc]

Re: VRO elimination issue

The enricher as you call it is actually a Fuel Primer Solenoid.

That makes it an enrichener. Enrichener is an unbrella term that inlcudes chokes, primers, and a variety of other devices to accomodate the needs of a cold engne that are a bit on the rich side of a stoichiometric ratio.

Thanks for giving me the lever position. I established this for myself by removing the enrichener (which in this case is a solenoid-actuated primer) completely, actuating the lever and observing which position would permit fuel to flow almost directly into the reed plate.

In each carburetor, there is a fixed brass high speed jet in the bottom center of the carburetor float chamber. Fuel must absolutely flow thru those jets before it can flow to any other passageway in the carburetors. It is best to manually clean those jets with a piece of single strand wire as solvent simply doesn't do that job as perfectly as it should.

Agreed. Not only did I clean the jets as you suggest, I inserted a tiny LED probe in to the bottom of each bowl from the top (with the bowl off) then looked through the jet (with the drain plug removed) to ensure it wasn't clogged. Niether of the jets to which you referred was clogged.

While it was at it, I also ensured that both float needles were operating as they were designed to operate.

I too suspect that fuel is not being 'processed' by the carburetors. But I don't know why. There is some possibility that a prior guy assembled both carbs incorrectly, or perhaps left something out -- and I compounded the error by repeating it (?). I do know that the owner (I'm in my pro bono mode) had someone "rebuild the carbs". I hate to buy a manual when I'm already working for free, but this task has morphed from one in which I offered to help a down and out friend to one that directly addresses my prowess with mechanical things. A schematic diagram of those carbs would sure be helpful.

 

[HighTrim]

Re: VRO elimination issue

Disregard the fact that these carbs have been rebuilt, since it was likely done wrong.

Follow Joes advice by removing the jets and thoroughally cleaning them. If you dont already have the special tool you will need to make one with a belt sander or the like. Pic compliments of FR



He is about as knowledeable as you can get on these outboards.

 

[halmc]

Re: VRO elimination issue

Disregard the fact that these carbs have been rebuilt, since it was likely done wrong.

There is some possibility that a prior guy assembled both carbs incorrectly, or perhaps left something out -- and I compounded the error by repeating it (?). I do know that the owner (I'm in my pro bono mode) had someone "rebuild the carbs".

Follow Joes advice by removing the jets and thoroughally cleaning them. If you dont already have the special tool you will need to make one with a belt sander or the like.

Agreed. Not only did I clean the jets as you suggest, I inserted a tiny LED probe in to the bottom of each bowl from the top (with the bowl off) then looked through the jet (with the drain plug removed) to ensure it wasn't clogged. Niether of the jets to which you referred was clogged.

The pictures of the tools are nice but the jets to which Joe and I are referring are FIXED

 

[tashasdaddy]

Re: VRO elimination issue

they are fixed meaning they are not adjustable, but you use the tool, to unscrew the the jets to clean them. as Joe mentioned above.

the red lever on this primer is in the run postion, any other position allows fuel into the intake, by passing the carb.

 

[halmc]

Re: VRO elimination issue

they are fixed meaning they are not adjustable, but you use the tool, to unscrew the the jets to clean them. as Joe mentioned above.

You may be right about the jets being removable. Let's see if Joe addresses the issue. If 'fixed' means not ajustable, all of the jets in these carburetors are fixed. In any case, the jets to which Joe refers are not clogged. I have cleaned them as joe says -- as I have cleaned jets for five decades -- and I have viewed light through each of them by means of the tool I mentioned.

The issue may be incorrectly or incompletley assembled carburetors, but it ain't clogged jets.

the red lever on this primer is in the run postion, any other position allows fuel into the intake, by passing the carb.

You're quite right.

 

[Joe Reeves]

Re: VRO elimination issue

Yes, fixed jets means non adjustable. Yes, they are removable but can be cleaned in place as you mention if necessary.

Obviously something is wrong pertaining to the carburetors. Perhaps fuel is not entering the csrburetors..... easy to check by removing the front lower float chamber screw plug.

Did the small round gasket that goes on the center brass high speed nozzle get installed?

The cam that slides against the carburetor throttle roller..... the scribe on that cam should make contact with the roller when the scribe mark is dead center with the roller. Not before or after. Check to make sure that the throttle butterflies just start to open when this alignment takes place. It's quite difficult to start a cold engine at a dead idle (closed buterflies).

I'm aware of what an enrichener entails. However, in this trade it is best to call the components by their given trade name, otherwise a lack of communication can develop rather quickly.

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

When time permits, visit my store at: http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store

 

[halmc]

Re: VRO elimination issue

Yes, fixed jets means non adjustable. Yes, they are removable but can be cleaned in place as you mention if necessary.

I cleaned 'em both in place. As is typical, both jets were pretty well wed to their threads, such that if I continued to torq away on 'em, they would be destroyed. However, the jets (referring to the jet in the bottom of each bowl) were not clogged to start with. Infact, the interiors of both carbs were very clean. Still I ran a small copper wire through the orfice and detected no debris. And with the LED, I could see light though 'em. The owner says the carbs were rebuilt by someone long before I came along and it appeared to be so. Trouble is, w/o a diagram of the carbs, it's fairly difficult to determine whether they were assembled correctly. But somewhat unlikely that the same error was made in both (each carb) instances.

On the topic of jets, is there any risk that any jets can be interchanged, i.e., installed in the incorrect place? As a veteran of AMAL's, I'm usually on the lookout for that sort of engineering, but didn't really check these carbs 'cause I had no reason to suspect incorrect assembly and the time I had 'em apart.

Obviously something is wrong pertaining to the carburetors. Perhaps fuel is not entering the csrburetors..... easy to check by removing the front lower float chamber screw plug.

Of course -- that's among the first things I did. Bowls are full. It sure seems like carburetion to me.

Did the small round gasket that goes on the center brass high speed nozzle get installed?

Yes, assuming I know which gasket you're speaking of. It's (from memory) round, about 3/4" OD, perhaps 3/8" ID, yes?

The cam that slides against the carburetor throttle roller..... the scribe on that cam should make contact with the roller when the scribe mark is dead center with the roller. Not before or after. Check to make sure that the throttle butterflies just start to open when this alignment takes place. It's quite difficult to start a cold engine at a dead idle (closed buterflies).

I'll check that. This engine starts fairly easily but runs lousy.

I'm aware of what an enrichener entails. However, in this trade it is best to call the components by their given trade name, otherwise a lack of communication can develop rather quickly.

I generally agree, but I think the potiential for confusion between 'enrichener' and 'fuel primer solenoid' is nil, especially when it isn't the focus of the conversation, unless we make it so.

Thanks for the directions on float setting. That's the sort of thing that the previous technican might have boogered up and I'll check both of 'em.

Good looking store, too. I wish you sold scans of a drawing of these carbs so that I could ascertain whether they are correctly assembled.

I've about endured enough punishment for this good deed and it's about time to deliver the whole schmear back out to the lake where it languished for a coupla years before I came along. Right now the boat and engine are gathering the notice of my neighbors, so a visit from the homeowners assoc can't be too far away. Plus it somewhat lessens my right to complain about the incessently barking dogs harbored by my otherwise civilized neighbors.

One last thought, and remember, I'm grasping at straws: I've never heard of a two stroke outboard suffering from leaky crankcase seals. It's somewhat common in the world of two stroke motorcycles -- a world in which I spent a decade or two -- but when it is the case, the engines show a taste for extremely rich mixtures as this one does.

 

[reeldutch]

Re: VRO elimination issue

the one thing that is overlooked often is the trothle shaft can leak air trough the trothle body(carburator) after soaking them in strong solvent those shafts should also be ruibuild.

drip some premix over the shaft and see what happens.

good luck

 

[halmc]

Re: VRO elimination issue

the one thing that is overlooked often is the trothle shaft can leak air trough the trothle body(carburator) after soaking them in strong solvent those shafts should also be ruibuild.

drip some premix over the shaft and see what happens.

good luck

Nice looking avatar, there, reeldutch. Care to part with the carbs?

 

[halmc]

Re: VRO elimination issue

Disregard the fact that these carbs have been rebuilt, since it was likely done wrong.

Very good advice, as it turns out, because a set of used carbs corrected the whole problem.

I bought a used set in a nearby town, cleaned them thoroughly, reassembled 'em and the engine runs great. I've not had time to discover what error(s) were made with the old ones, but I think missing parts may have been the issue.

The used carbs came from an '84 Johnson 50. These carbs have what appears to be an adjustable idle jet (adjustable needle, actually) and an extra place to connect a hose. To be specific, each carb has three hose connections: 1) fuel inlet 2) primer hose; and 3) ??? I've attached a .jpg and ask for help in identifying what this port is for.

Also, is the adjustable needle an adjustment to air or to fuel? In other words, if I screw it to the seat, does that shut off idle air or idle fuel.

Thanks!

 

[seahorse5]

Re: VRO elimination issue

The adjustable idle needle regulates the fuel flow at low speeds, not air.

The extra "port" on those carbs is for a hose between both carbs to act as a balance tube. It was only used for a few years.

Your original problem with the carbs not "feeding" correctly may have been a clogged or restricted idle fuel tube that goes from the bowl up to the idle passageway. It is super small with a restrictor are inside and will clog up with the smallest spec of varnish or debris.

 

[halmc]

Re: VRO elimination issue

The adjustable idle needle regulates the fuel flow at low speeds, not air.

As I figured, thanks!

The extra "port" on those carbs is for a hose between both carbs to act as a balance tube. It was only used for a few years.

Good, that's the way I connected 'em up, Thanks again.

Your original problem with the carbs not "feeding" correctly may have been a clogged or restricted idle fuel tube that goes from the bowl up to the idle passageway. It is super small with a restrictor are inside and will clog up with the smallest spec of varnish or debris.

The carbs are on my bench: That tiny little tube is free and clear on both carbs.

 

[reelfishin]

Re: VRO elimination issue

If a parts breakdown of the carbs will help, try this:
http://i32.tinypic.com/2552mbn.jpg

 

[clanton]

Re: VRO elimination issue

Halmc

I will be back Panama City next week, I can look at engine when I come thru your city. I have Oem manuals and special tools needed you may use if needed located in Panama City.


Clanton