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| Bogging down at high rpm http://mudmotortalk.com/mmt_v2/viewtopic.php?f=3&t=71720 |
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| Author: | tyler_johnson [ Tue Dec 12, 2017 4:54 pm ] |
| Post subject: | Bogging down at high rpm |
Alright got a buddy with a GTR with mikuni, heads, roller rockers, the works, and when he is running about 3700 or so RPMS it seems like it boggs down and just sucks at life. Any ideas? Sent from my Pixel XL using Tapatalk |
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| Author: | BlueShamu [ Tue Dec 12, 2017 5:26 pm ] |
| Post subject: | Re: Bogging down at high rpm |
Need more info. Is he trimmed right? Is this WOT? What size boat? Loaded? Light? What prop? Sent from my iPhone using Tapatalk |
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| Author: | tyler_johnson [ Tue Dec 12, 2017 9:12 pm ] |
| Post subject: | Re: Bogging down at high rpm |
trimmed different angles to see, and yes WOT, 1750 boat loaded with 2 people and duck shit, and gator tail 2 blade. |
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| Author: | Will C [ Tue Dec 12, 2017 10:38 pm ] |
| Post subject: | Re: Bogging down at high rpm |
valve adjustment too tight,,, or tune is way off,,, or just starving . Y'all try pumping bulb while it bogged? Just throwing out ideas |
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| Author: | tyler_johnson [ Tue Dec 12, 2017 10:45 pm ] |
| Post subject: | Re: Bogging down at high rpm |
Unfortunately I haven't been there when the crap is happening. I am gonna try some stuff in his boat in a few days and report back. Sent from my Pixel XL using Tapatalk |
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| Author: | MaXXis85 [ Wed Dec 13, 2017 7:00 am ] |
| Post subject: | Re: Bogging down at high rpm |
Basics. Air, Fuel, Spark. Valve lash leak test. |
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| Author: | brycecheramie [ Wed Dec 13, 2017 7:39 am ] |
| Post subject: | Re: Bogging down at high rpm |
Also, with those mods, he should be at better rpms. |
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| Author: | tyler_johnson [ Wed Dec 13, 2017 1:18 pm ] |
| Post subject: | Re: Bogging down at high rpm |
yeah He normally runs 4400+ but said when it hits right around 3700 it acts like it is starving for fuel and nearly just shuts down, but if fine up until that point. |
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| Author: | Glider [ Wed Dec 13, 2017 3:39 pm ] |
| Post subject: | Re: Bogging down at high rpm |
It sounds like a fuel pump going bad, trash in the main jet or something preventing fuel delivery. I took my boat out once and it ran fine for a while then would bog down and die. I could wait a few minutes and it would crank and run for a short time and die again. The problem turned out to be the vent on gas tank. If your buddys engine runs fine but bogs at a certain throttle position that sounds like a lean condition(not enough fuel). He might try pulling the plugs and see if they are whitish. The pumping primer is a good suggestion also. Come to think it could be a clogged fuel filter as well. Hope this helps. |
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| Author: | tyler_johnson [ Wed Dec 20, 2017 11:44 am ] |
| Post subject: | Re: Bogging down at high rpm |
So before I could really diagnose, my buddy took the guys head off (after compression was fine), and I had already figured out there was no spark going to the cylinder. Broke a head bolt off in the block by using the torques wrench incorrectly. So that is where I am at, trying to get a bolt out of the head and those damn bolts are hard as shit! |
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| Author: | MaXXis85 [ Wed Dec 20, 2017 3:23 pm ] |
| Post subject: | Re: Bogging down at high rpm |
9mmx1.25 |
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