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Discussion Starter · #1 ·
So I have recently bought a new boat, definitely not a microskiff...  It is a 23 foot Rabolo with a 225 Evinrude Ocean Pro.  The motor has spark on all 6 cylinders as well as good compression on all 6 (110 on 5 of them and ~107 on the bottom port cylinder)

So got spark, got compression should run right!!  Bought the whole rig with out seeing the motor run.  Sprayed some starter fluid down the carbs and it came to life for a few bore strokes, everything sounded normal.  Has to be a fuel system problem


Got the rig home, cleaned her up and hooked up a 6 gal gas tank with premixed oil.  Disconnected the vro system (oil injection system)the way the manual says to do it.  Tried to start it and nothing. 

Since then I have check the fuel pump, fuel primer, fuel hose routing, recirculation hose routing.  All word by word out of the manual and all check out with in spec.  The guy told me that he had rebuilt the carbs so I have a feeling it has something to do with that, but I am stumped, short of taking all 6 carbs apart.  But if you remember I suck at tuning carbs.  I can rebuild them, get them roughly runing, can not fine tune to save my life.  And that is  with just one, this motor has 6!! 

Any bright ideas here?  The motor looks clean as a whistle.  The carbs on this motor are made of plastic and supposedly dont gum up according to the guy I bought the rig from :eek:

any questions or info that I forgot feel free to ask.  I am stumped here.  Even went through the "fuel system trouble check chart" and pretty much checked everything off that they list as a possibility.

I really dont want to take this thing to a mechanic, not even because the money. I feel I should be able to do this... I just am asking for a little brain stimulus :)
Any suggestions are welcome...
 

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I know you're tired of hearing me say "Test Ride"
and I'm sure you know my other favorite is "Get the OEM shop manual!"  ;)

Outboards all have the same basic requirements:

Fuel
Air
Spark (at the right time and place)
Compression
Lubricant

When I buy a used motor I go with the assumption nothing's been done in a long time.
So I always do a complete service.

Compression check (which you've done)
Vacuum check (to verify intake vacuum integrity...no air leaks)
Replace all filters in fuel system
Check fuel pump pressure (if bad replace pump)
Replace all spark plugs, set gap per specs
Check spark intensity with a spark gap tester
Check/adjust ignition timing
Replace water pump and housing
Drain and refill lower unit (replace screw seals)
Change crankcase oil and filter (4 stroke)
Grease all zerk fittings
Rebuild carbs, and synchronize the linkages.
Check quality of fuel in tank (water or dirt contamination)
Replace fuel lines

All that will kill a weekend or two, but it's the only way to make sure the engine will run properly. Did I miss anything?
 

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Discussion Starter · #3 ·
Believe me I know test ride should be a must.  But there are certain deals in life that come along that make you say forget the test ride ;)

As for the shop manual I have it.  Like I said all the test that I have done have been word for word out of the manual.

I know I have spark and compression on all 6 cylinders, so it has to be a fuel issue.  I have tried everything that I can think of short of rebuilding the carbs and testing the vacuum system.

Last night, I tried one more thing.  I realized that all the pictures in the shop manual have a big plastic cover over the carbs, mine doesn't :eek:  So I took off my shirt and folded it into a square, covered the carbs, had the wife turn the key and VVRRRMMMMMM :D :D :D 
So could it just be that I am missing the plastic plate and there is not enough back pressure on the carb side?  Or My intuition tells me this is where checking the vacuum system comes into play :-/

Compression check (which you've done) check
Vacuum check (to verify intake vacuum integrity...no air leaks)  on my list of things to do, timing just was not right until now, will do this today!!!
Replace all filters in fuel system check
Check fuel pump pressure (if bad replace pump)check
Replace all spark plugs, set gap per specs check
Check spark intensity with a spark gap tester check
Check/adjust ignition timing I am a scared chicken
Replace water pump and housing Lets get it running first
Drain and refill lower unit (replace screw seals)  Lets get it running first
Change crankcase oil and filter (4 stroke) NA
Grease all zerk fittings check
Rebuild carbs, and synchronize the linkages.  I am a scared chicken
Check quality of fuel in tank (water or dirt contamination) check
Replace fuel lines check

As for if you forgot anything... I am still stuck, one step closer but still do not know what the problem is. What does the shirt over the carbs and it fires up tell you? Do you think it is the vacuum system or just the stupid plastic cover? To me the cover should not make that big of difference right?
 

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;D You found a new one!  ;D

Runs better with the carbs covered in shirt.  [smiley=happy.gif] (that'd be a neat bumper sticker)

Which means that she'll run choked.
Sounds like an air leak on the intake side, too much air, not enough fuel.
You said previous owner did a carb job, sounds like on reassembly something was left loose or off.
 

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The motor should run without the cover, it's just there to keep t-shirts from getting sucked into the motor. ;D

Seriosly, I run mine without the cover when I check to see if all the carbs are getting fuel to the cylinders.

Like Brett says, this guy did not rebuild the carbs right or something. If you get stumped I can give you the name of my mechanic who is really good and will show you what he is doing so you can learn along the way. His hourly rate is about the same as anybody else but he is honest and knows his chit so you won't be billed for guess work.

He is mobile so I don't know how far he will drive but you are welcome to use my driveway.
 

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Discussion Starter · #6 ·
OK so other things have been in the way of working on this but here is where I am at. 

Pulled off one of the 6 carbs and took it apart.  Everything seemed clean and normal.  There is a high speed orifice and a intermediate orifice, then a low speed jet.  I dont think the guy could mess it up, pretty intuitive.
I did notice that on the side plate of all 6 carbs the gasket looked kinda warped.  Seems to be flat in the area that is sandwiched between the throtle body and the plate but warped out side of it... like this:




So to recap:
Motor will run but have to use the shirt method to get it started the first time

Once started once, you can turn it off and come back a min or so latter and restart.  Have not tried an extended period of time between starts yet.

Once running, motor bogs out if I gas it

Checked one of 6 carbs and it looks clean

SO...   I would think it was a choke issue, but the fact that it bogs out when I give it gas contradicts that thought and says carbs are not tuned right.  There is only the one low speed adjustment, everything else is a fixed orifice and can not be adjusted. 

I dont know enough about carbs to not hate them at this point :D
 

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Your best bet for this problem would be this group.

http://www.marineengine.com/

Membership is free, at least it was when I joined.
 

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Discussion Starter · #10 ·
OK so I went back and re-read everything that we have said. Brett you said that "Runs better with the carbs covered in shirt. Smiley (that'd be a neat bumper sticker)

Which means that she'll run choked.
Sounds like an air leak on the intake side, too much air, not enough fuel."


Combine that with the picture of the side cover plate gasket and that might just be the problem. When it idles it idles a little bit high on the rpm side, would that confirm the to much air thing?
 
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