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Discussion Starter #1
hello:
my Grizzly 660 makes some explosions in the admission that cause a drop in rpm that causes the shutdown if it does not have a high idle speed. cold it shows more.
 

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I'm guessing you mean it back fires threw the intake / carb?


-If so, clean carb and verify it's settings and check the intake boot to the engine for cracks etc...
-fresh fuel if not already done.
-New spark plug
-Have the valves been adjusted recently? if not mite be your issue.
 

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Discussion Starter #3
-Have the valves been adjusted recently? if not mite be your issue.
I did valves adjustment and I do not notice any improvement;
looking at the manual I had the doubt of the coincidence of the marks in which of the 2 turns is to make the adjustment, doubting which lap is the compression, if the one that has more or less distance between valves and rocker or the other
 

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Discussion Starter #4
I'm guessing you mean it back fires threw the intake / carb?


-If so, clean carb and verify it's settings and check the intake boot to the engine for cracks etc...
-fresh fuel if not already done.
-New spark plug
It explodes for the carburetor, I'm uploading a video so you can see it

the boot to the engine has a crack, I'm waiting for a new one,
but before cracking already towards the explosions and I fear that the new one cracks because of the explosions.

fuel it´s fresh, spark plug oem new
 

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The mixture screw might need adjusting, you can put electrical tape around the rubber manifold crack to stop air leak for the short term & turn mixture screw out 1/8 turn at a time to see if it helps, carby might need service, you have manual so your one step ahead.
 

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Discussion Starter #6
What carburetor repair kit do you recommend?
I have seen on Aliexpress from € 7,
I do not know what result they give.
To regulate the lower mixing screw with the engine running you have some useful or what do you do?
Thanks
 

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If the kit is for your exact year & model it should be OK. plug does look a bit lean but todays fuels make it really difficult to make a decision. Have you turned the mixture screw out 1/8 turn yet? With the engine warmed up you turn the mixture screw in(or out makes no difference) until idle changes then turn other way to get the highest idle, if you go to far the idle will lower, just turn screw back to highest idle, the movement of the screw is very small, go a little bit at a time(it takes a bit of practice) concentrate on listening to the exhaust sound as it goes up or down, the really hard part is getting at the screw to adjust it.
 

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Discussion Starter #10 (Edited)
https://youtu.be/39oLlZAgRQw

in the video you can see that by keeping the start button pressed, the motor always remains for a moment without turning when it gets harder, as if it had little battery, but with a new charged 75Ah battery it does the same; Will the starter cable be rotten? The starter motor is fine.
 

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Discussion Starter #11
with what tool do you make the adjustment? I can not finely adjust with the engine heat and vibration. approximately how many turns do you have the screw? every time you adjust the height of the needle you must adjust the bottom screw right?

Thanks
 

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Your last vid was too dark to see(for me) where that spark flash was coming from BUT the high tension lead from the spark plug will do that, replace it if that's where it's coming from, can you get a pic of that area with more light in it?? Do not ride it until you cure the spark problem, that spark could ignite any fuel leak
 

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Discussion Starter #14
Your last vid was too dark to see(for me) where that spark flash was coming from BUT the high tension lead from the spark plug will do that, replace it if that's where it's coming from, can you get a pic of that area with more light in it?? Do not ride it until you cure the spark problem, that spark could ignite any fuel leak
it's for crack of intake boot to carburator, no problem
 

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Wow, that's one hell of a manifold crack! Until you get the new rubber manifold it's not much use trying anything else as the crack will be sucking in air causing a lean mixture & probably the popping, just for a giggle wrap some electrical tape over the crack(to seal it) when the engine is cold & see what happens when it's started.
As for a mixture screwdriver I use a super short stubby screwdriver or from motor shops & hardwares you can get a kit with all sorts of bit heads in it, there usually cheap & have a flat head bit in them, for the heat I have thin exhaust gloves or piece of scrap denim clothing(single layer), heavy cloth etc, lay it under carb & up against the cylinder this will help a bit, it also catch's stuff you drop when you get burn't :grin2:
 

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jonnye... After you replace the intake boot. Adjust the valves again. Use the - mark on the flywheel. Check for TDC by removing the spark plug. While holding a finger over the spark plug hole rotate the engine until you feel the compression stroke. When the piston is near the top then carefully locate the - mark.

When at TDC and if the valves are set correctly the rocker arms should be loose.
 
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Discussion Starter #18
Thank you.
When I translated the manual, I had some doubt.
The similar brand to an H for what is it? it's near I
 

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Discussion Starter #19
What do you think of the starter being stopped a moment before continuing to spin until it starts?
It seems as if there was a point that becomes very hard, pulling the rope I can not move it at that point.

Could it be that the engine that makes more compression has some modification or will it need a new starter and the rope only serves to help the starter if the battery is low?
 

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The battery issue could be bad earths on the frame, all contacts have to be wire brushed, bolts brushed & paint removed from the frame where the leads go, it's that important, with a 75AH battery(sounds like something from a truck!)it should turn over like a sewing machine & don't trust jumper leads to do the right thing either, I've seen them fail, the other thing I've seen is corroded leads internally, where the wire gets clamped to the terminal it corrodes between the terminal & the wire, this mainly happens near the sea or in a garage with things like paint thinners, any white spirits that don't have an oil base & damp areas, it happens.
Did you bother to try sealing that manifold crack? There's a reason I suggested to do it, it's possible that there are multiple problems in the same area.
 
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