Ovation bog and lean out

3

3wheelerdude

Member
Joined
Jan 30, 2011
Messages
32
Age
43
Location
Canada
Alright, my first post!

This, new to me 89 Ovation has me scratching my head.
Its got a '99 engine in it, and runs pre-mix.
It will start great, then when at about 1 third throttle it will bog down.
The plugs are on the white side, so I beleive it is running lean but does not explains the bog.
I had the carbs appart(that weird looking dual/single carb) and everything looks good. New plugs, drained fuel tank and a fresh mix of 40:1.
I also took the fuel pump appart and again it looks to be perfect.

Fuel mixture screws were set at 1 turn out when I got it, and I changed that to 1.75 and 2 turns out while trying to tune it with no results.

Anyone has an idea???

Thanks
Joe
 
how we're the plugs you took out when replacing with new ones?
 
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have you cleaned the primary clutch lately? debris and dust will build up and can cause this.

need to check the crank seals for air leaks for the lean problem.
 
The plugs had a black/dark brown ceramic, with the tip of the electrode being withish. I am not sure this indicates a lean condition, as usually the ceramic will be with and not only the tip of the electrode.

And no I have not checked the clutch as I though it was engine related, but if you say the primary might cause these symptoms, I will definatly have a look at it.\\

Thanks guys.
 
Mikuni VM-32/34

3wheelerdude said:
This Ovation runs pre-mix.
It will start great, then when at about 1 third throttle it will bog down.
The plugs are on the white side, so I beleive it is running lean but does not explains the bog.
I had the carbs appart (that weird looking dual/single carb) and everything looks good.
New plugs, drained fuel tank and a fresh mix of 40:1.
I also took the fuel pump appart and again it looks to be perfect.

Fuel mixture screws were set at 1 turn out when I got it,
and I changed that to 1.75 and 2 turns out while trying to tune it with no results.

Anyone has an idea ???
Click to expand...

Throw that odd & funky "Teikei" carburettor in the trash can and put in an ordinary Mikuni VM-32/34 instead.

The engine will run like a champ ;)!


:2strokes:
 
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If I can get my hand on an ET 340 carb with intake manifold, then I would replace the carb, but for some reason, I dont think thats the problem.

- I took the primary appart and the spring without tension mesured 3 inch. Anyone as the specs for this spring, as I would like to figure out if a weak spring is the culprit.
 
3wheelerdude said:
I took the primary appart and the spring without tension mesured 3 inch.
Anyone as the specs for this spring ?
I would like to figure out if a weak spring is the culprit.
Click to expand...

I do not have the specs for the spring when it is NEW. *sorry* :o|

But this picture is of the stock "GOLD" spring from my daughter's Ovation...



It is slightly less then 3"



:2strokes:
 
Well thanks alot Lasse. Its the same height as mine, and mine also has the gold marking. So I can eliminate the spring as a potential problem.

Now could the secondary cause bogging at higher speeds...?
 
Update :

3wheelerdude said:
I took the primary appart and the spring without tension mesured 3 inch.
Anyone as the specs for this spring ?
As I would like to figure out if a weak spring is the culprit.
Click to expand...
UPDATE :

I have done a little tecnical digging...
...and the "GOLD" YPZ clutch spring should be 73.40 mm when NEW !!!



:2strokes:
 
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Lasse said:
UPDATE :

I have done a little tecnical digging...
...and the "GOLD" YPZ clutch spring should be 73.40 mm when NEW !!!



:2strokes:
Click to expand...

That sounds about right doesnt it? It sits at almost 3 inches, as per picture, and 73.4mm converts to 2.88 inches.
 
3wheelerdude said:
Alright, my first post!

This, new to me 89 Ovation has me scratching my head.
Its got a '99 engine in it, and runs pre-mix.
It will start great, then when at about 1 third throttle it will bog down.
The plugs are on the white side, so I beleive it is running lean but does not explains the bog.
I had the carbs appart(that weird looking dual/single carb) and everything looks good. New plugs, drained fuel tank and a fresh mix of 40:1.
I also took the fuel pump appart and again it looks to be perfect.

Fuel mixture screws were set at 1 turn out when I got it, and I changed that to 1.75 and 2 turns out while trying to tune it with no results.

Anyone has an idea???



Thanks
Joe
Click to expand...



Im having the same issue. Did you figure out what happened?
 
Clutchburner said:
I'm having the same issue.
Did you figure out what happened ?
Click to expand...
Throw that odd & funky "Teikei" carburettor in the trash can and put in an ordinary Mikuni VM-32/34 instead.

The engine will run like a champ ;)!
 
Clutchburner said:
Im having the same issue. Did you figure out what happened?
Click to expand...

Yep, figured out that the jetting between 89 and 90 models is completly different. So this 89 Ovation had a 90's carb. Changed the jets from 170's to 140's and it runs like a champ.

Still running the oval crab in 3 different ovations, and they all run good.
 
Ive had the carb apart so many times and tried countless things and after about 30 minutes the thing just wont do anything but idle unless i shut it off for a few minutes but even then it doesnt run long.
 
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