93 Johnson 150 - Starved for fuel - wont quite start up

[spencroy]

Hello Everyone.
I currently am debugging a short somewhere in my tilt/trim which causes the main fuse to blow when connected.

However, when the tilt/trim is disconnected at the motor, I am able to fire the starter without blowing the fuse (fuse remains cold, no heat) and the engine cranks. The problem is she just wont quite turn over (or if she does, she wont stay running)

It is almost as if she isnt getting fuel.

I was able to get her started by cleaning the carbs, and then spraying some starter fluid in there, but she only ran for a second and then puttered out. I assume this means that I have spark as she ran for a couple of seconds (she sounds like a good engine if I can just get her running)

My next test will be to premix oil/gas, disconnect the fuel line from the tank and run the mix straight in. Is this a good next step?

Additional information. When I remove the carb cover there is a little red knob that I can turn. When I rotate counter clockwise and push the prime bulb, gas flows out each of the 6 cyls. I am hoping this means I have good gas flow. Any tips on what that red adjustment does, and what I should have it set to (closed, wide open, somewhere in between)

Any tips on debugging this type of problem would be greatly appreciated.

Quick History: this boat has been idle for many years. I just bought it from the family of the original owner who died recently (natrually they told me the boat was fine when he died.. why is it all boat sellers are liers?)
Roy

 

[tashasdaddy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

read the TOP SECRET FILE, 1st thread in this forum.

 

[spencroy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Thanks Tashasdaddy, I should have read that, but the Top Secret thing threw me off a bit. Let me diguest this info.

Thanks for the tip.

 

[spencroy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Short Version:

After a weekend of debugging I have 2 specific questions:

1. Should I be reading 10.11 Volts on the Tan (Horn) wire at all connections on the engine (both temp wires, the Amphenol connector for the VRO2, and the vacuum switch)

2. Can you review my diagnosis, confirm or deny, and suggest where I might find the part? - I will post the full description now for that issue.

 

[spencroy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Long Version:

First lets recap the symptom. I prime the bulb, it grows firm. With the key depressed (choke) and turned to start possition the engine fires up just fine. However, after about 5 seconds the engine rpms back off and the engine dies.

If I reprime the bulb I can duplicate this multiple times.
---

What I have done so far. Based on Tashasdaddy's suggestions I reviewied the top secrete file and before tearing into the carbs willy nilly (the carbs appear to be in really good shape, and the engine runs fine for a short period of time causing me to suspect my carbs and spark are ok) I remained focused on the fuel delivery system.

I started by replacing the primer bulb and lines.
I inspected all lines (fuel, oil, recirculation, vapor, primer assist) all seemed to be ok and no evidence of leaks.

I then ruled out the gas tank by supplying the fuel directly from a 1 gallon tank premixed with oil.

I then spent all day Saturday really trying to understand how the entire fuel system worked. I thought at first my issue was electrical to the fuel pump assembly (VRO2). The issue I noticed:

With Key On:
Black/Purple = Got 12V as expected
Black/Tan = got 10.11V - got confused
Black/Grey = no volts (as expected?)

I struggled with trying to figure out why all my Horn wire connections were showing less than 12 V and figured it was a short. All horn wires on the engine come in at 10.11

However, I finally stoped fooling with that when I was still able to duplicate the exact same startup behavior even with the Amphenol for the VRO2 disconnected. This caused me to conclude that my issue was probably not strictly electrical (and I cant see how the horn would prevent startup anyway)

So I drove on....

I disconnected my main fuel supply lines from the fuel delivery sytem back to the carbs (at least that is what I think I did)
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At this point I wanted to test the fuel pump operation. I thought that if I had this fuel line disconnected to the carbs, and turned the key over, that fuel should come out of the line (is this valid?)

It did not, so I surmized my problem was in the fuel pump somewhere
--------------------------------------------------------------------
I began my disassembly of the fuel system. I tested each line and the float, everything appears to be ok (but I still dont understand where the float needle is exactly)

Please verify my understanding of the following picture:

Based on the OMC Service Manual I ran the following test:
I applied 15lbs of compressed air to the "pulse hose connection" in my picture above. The VRO2 clicked and held pressure (so far so good)

Then the book says if you "cover the fuel outlet" which I assume is the grey thing labled "1. fuel outlet" in my picture above, that you should be able to remove the pressurized air, and the pump should hold....

It did not. The pump immediately clicked and the flow chart says "Install fuel pump diaphram kit" (although I still dont understand exactly what that means)

With this discovery I decided to take the VRO2 apart. I found the following:

I belive that is my defect. When the spindles of the two plastic parts of the part are aligned correctly, it does feel like this was a complete part. I belive the part is called the "Intermediate Housing" but I am not certain about that.

Assuming this was designed to be a single part, I went out to BRP to try and find out more about it.

The problem there is the VRO2 is not exploded on BRP. The only thing that is listed is the entrire VRO2 unit.

Assuming that this part is indeed defective, can anyone suggest where I might find a replacement?

Also, am I off in the weeds? Does this sound like I am following the correct debug approach?
Thanks
Roy

 

[spencroy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Found a diagram that does seem to indicate the VRO2 part I described should be a single part:
http://www.maxrules.com/lots/VROpic.jpg

90 bucks is sure better than the cost of replacing the entire thing.
Roy

 

[Silvertip]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

The very first test you should have done before chasing your tail is when you do get the engine to fire, continue to squeeze the primer bulb. If the engine continues to run you have a fuel delivery problem that is very idicative of a bad fuel pump. Since lack of fuel is evident, that should have been your first check.

When you disassembled the carbs and removed the float, the inlet needle (pretty self explanatory) is what the float operates. When the float bowl is full the float rises and pushes the inlet needle against the seat and shuts off the fuel supply.

 

[daselbee]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Hello Everyone.
I was able to get her started by cleaning the carbs, and then spraying some starter fluid in there, but she only ran for a second and then puttered out.
Roy

Hey Roy....

I see you are steadily proceeding with fixing up your motor.
And you have the T/T short problem fixed...
So, I want to warn you with all sincerity....do not use starting fluid when trying to get that motor running.
Here is why...two main reasons....no oil in the starting fluid, and it can wash the cylinders clean of oil and now you have a dry motor.
Next reason...and I swear by this....the ether in the starting fluid will bubble and craze the inside of the plastic carb venturis, permanently damaging them.
You may not think that the roughness and crazing would cause any problems, but it does.
The roughness and crazing alters the airflow thru the venturis and causes turbulence where there would not normally be any. That reduces the amount of pressure difference from the front to the back of the carb, and it does not suck as much gas from the bowl when running. Then you have a lean running cylinder, and it will burn up. I would estimate about 12 to 15 hours and you will lose a piston. Seriously.
So, if you have plastic carbs, very carefully examine the venturis of the carbs you sprayed starting fluid in. You MUST replace those carb bodies if they are rough.

Just my 2 cents.

 

[daselbee]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

The very first test you should have done before chasing your tail is when you do get the engine to fire, continue to squeeze the primer bulb. If the engine continues to run you have a fuel delivery problem that is very idicative of a bad fuel pump. Since lack of fuel is evident, that should have been your first check.

When you disassembled the carbs and removed the float, the inlet needle (pretty self explanatory) is what the float operates. When the float bowl is full the float rises and pushes the inlet needle against the seat and shuts off the fuel supply.

Not sure Silvertip, but I think he is referring to the float he found in the vapor separator.

 

[spencroy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Hey Daselbee,

first off, yes, that is correct I am talking about the float in the fuel vapor separator. This is the image that I dont quite understand in the Service Manual

I am struggling to make the jump from what I see in reality to what is in that diagram labled "20".
--

As for the starting fluid thing, after your first reaction I have not used starter fluid again. All testing I am doing at this point (and since that one test) has been using fuel directly from a 1 gallon premixed container. However, it is nice to have the logic behind why not to use it as opposed to simply "dont use it". I appreciate the explination.

 

[spencroy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Hey Silvertip,
Thanks for the suggestion of repriming the bulb while its running. I would have ran into a problem though as I was testing by myself and couldnt have made the run from the starter switch to the bulb

I referenced which needle I am talking about in my previous post.
Thanks.
Roy

 

[daselbee]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Roy,
Your pics are a bit blurry of the float and needle and seat from the book, but if you are reading in the carb section, and trying to visualize the book against what you are seeing in the vap.sep., it won't match up.
Each carb has it's own needle and seat and float. Six of them. Plus the one you found in the vap.sep.
If I were you right now, I would put it all back together (vap. sep.) trying not to disturb the mechanical parts inside the vap. sep.
Since you have torn into that VRO pump, I would buy a new fuel pump (ouch! $$$) and install it. There have been many posts on here about the success/failure rate of trying to rebuild a VRO pump.
Be sure to install the new pulse fitting that should come with the fuel pump
and make doubly sure that all hose connections are tight and sealed. No fuel leaks, no air leaks.

I have quite a few suggestions on your electrical questions too. The electricals are not as complicated as you may be thinking.
PM me your phone number and I will be glad to call you.

 

[spencroy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Uggggh.. that is not what I was hoping for.

would buy a new fuel pump (ouch! $$$) and install it. There have been many posts on here about the success/failure rate of trying to rebuild a VRO pump.

This morning I was faced with the decision of getting a new pump ($345 - $398) or a rebuild kit for $90.00 which contains my suspected failing part. As such I decided to go with the rebuild kit as this picture really seems to show the part I need
http://www.maxrules.com/lots/VRO_Kit.jpg

So, I opted for the 90.00 option. I will see how the rebuild goes, but now I am depressed because if I have to pay another 400 on top my wife is going to loose it

sending you a pm with my contact info (as soon as I figure out how to).
Roy

 

[spencroy]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

Hey Guys,
Just wanted to provide an update on this one. I recvd my VRO2 rebuild kit from MasterTech Marine on Friday last week. I took it to the shop Friday night and began the rebuild. The only thing interesting in the kit is they sent me an extra gasket that is either just not for my unit, or not required at all.

The other pointer is that on my first rebuild I missed a seal and the unit was not working. If you rebuild this VRO unit you need to be aware of the flow chart:
http://www.maxrules.com/graphics/VROpics/VROflowchart.jpg

This helped me solve my issue.(which was a seal which was not seated properly)

Spent Saturday night fishing, and Sunday out with the whole family (including Mom who got to play in the lake for Mothers Day!!!). Thanks so much for the excellent advice in this thread.

On the water
Roy

 

[jonesg]

Re: 93 Johnson 150 - Starved for fuel - wont quite start up

So it runs now, good.

if you read long enough here you'll see rebuilt pumps don't always work out long term but you can always opt for the fuel only pump, no VRO.
Then just premix your own fuel and oil.
The sierra fuel only pump is very reasonably priced.