Think I found my WOT problem...

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Well after my weekend run mymotor was pulling good, minus a minor stumble when I was WOT and it seems like it's taking in to much fuel and cant quite burn it. When I pull back to 3/4 throttle it cleans up and stumble goes away. Stumble is more of a Studder. Its nothing serious but to somebody with a good engine Ear I can feel it and hear it.

So I got home pulled the plug and the plugs were fuel soaked, Not completely washed out or fouled...just enough to notice that they were taking in to much fuel

Here's a pic...hard to see the fuel but you can see it on the Electrode where it meets the Spark plug body :





This afternoon I took all the carbs off one by one to clean, and check float heights. Well needless to say 4 Carbs were way out of Spec. 1/8 inch up to a 1/4 inch past the gasket base. They were definitely to high, then I found two retainer clip on the needle vales wrapped around the Float rod. Whoever was in the motor last had taken the retainer clips and run the float rod through them. Needless to say the Needle valve was stuck.

Here's some carb pics from start to finish :




Carb number one :

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Carb One Float :



Set screw removed off Float rail :



Float and rail removed :



Needle valve pulled for cleaning :

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Float adjustment (My index finger on it) You slightly bend the plate to set float height :



Re-install set screw on float rail and check float height with straight edge :



Float height set and ready to get re-installed :

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Here's the 2 Carbs I found that had the Retainer clip installed completely wrong and were the culprit of my Fuel issue at WOT :



You can see this was clearly installed incorrectly and was definitely human error because there is no way the retainer clip can get wrapped around the float rail like that :







Here's the Manual and the actually carb side by side...you can clearly see the retainer clips proper installation in the manual :






I put every carb back together ( Blue locktight on the carb bolts ) and fired it up, seems to run better but I will know Saturday when I take her back out!

The previous owner of this motor brought this motor to 3 well known techs and Marinas to chase down this problem and after 2800 dollars spent it still had this problem.

[Rut311969]

Hope this fixs prob and goes to show ya some time its only gona get fixed if you do it yourself .

[77viper]

I can't say that I have ever seen anyone run the pin through the retainer before, I wonder what they were thinking. I have to have the fuel level set way low on my viper or else the fuel sloshes and blocks the vents on take off. I also run a holly red pump so there is plenty of volume when needed.

Good find

[S P E E D]

Hope this fixs prob and goes to show ya some time its only gona get fixed if you do it yourself .

You can say that again...I cant believe how much stuff on this motor was incorrectly wired, installed and or just butchered. One thing this has done for me is really get familiar with these motors.

I can't say that I have ever seen anyone run the pin through the retainer before, I wonder what they were thinking. I have to have the fuel level set way low on my viper or else the fuel sloshes and blocks the vents on take off. I also run a holly red pump so there is plenty of volume when needed.

Good find

I've heard of guys setting low like you are, You think this would benefit the average Boater? Like everyday boating and a few top end passes? Also its funny you mention the pump because I had though about a fairly low PSI booster pump so to speak. The previous owner of this motor had said when he got the motor the guy had given him a parts bin and it had a fuel pump and Adjustable Fuel pressure regulator. What kind of Pressure do you run off that Red holley Chet? also do you delete the factor low psi pump? I'm curious...something I might want to do.

[jacklake2003]

Very informative post! Thanks for taking the time to share.

[silkeysak]

Hey Speed, It looks like a mechanic did that on purpose to keep somebody coming back. Didn't that same guy pay his mechanic $2800 for a powerpack and a fuel pump? Somebody saw him coming and he sold his motor over those retainer clips! As far as your compression goes, these motors were rated at 100 lbs compression from the factory, so you're good. You could try a decarb and they might come up more. Like I told you before, Ive seen as much as a 12lb increase on a lower than normal cylinder from getting the carbon off the rings. Decarb with 1 can Seafoam, 3/4 gallon of gas, add 2 cycle oil. Works like a charm. If it's still smoking, do it twice. Have fun and LET ER EAT!








79 Viking 225 Loop

[YDOC462]

Very informative post! Thanks for taking the time to share.

thanks