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| Help! Motor issue http://www.mudmotortalk.com/mmt_v2/viewtopic.php?f=3&t=23940 |
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| Author: | duckhunting84 [ Fri Nov 11, 2011 3:28 pm ] |
| Post subject: | Help! Motor issue |
I'm looking for some help, I have a stock 35 mud buddy hyper. It has. 36 hours on it. I have set the gov on it, and turn 4160 rpms out of water. Been running great all summer and fall. Then while I'm out hunting this last week, it won't turn any faster than 3500 rpms in water. I still get the same out of water rpms as I did before 4160. I talk to the guys at mud buddy, they thought it may be water in fuel, carb icing. I followed their directions with cleaning the carb, new fuel, and heet in the fuel. I went further and put new plugs, auto lite, and a new fuel filter. I go out hunting, and it starts out bogged down at 3500 rpm and as we motor out to the spot, it slowly climbs up to normal rpms, and is running great. After the hunt we head back and it's back to running 3500 rpms. I can't figure this thing out? Sorry for such a long post, just wanted to give as much info as I could. Any ideas of what could be causing it? |
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| Author: | Team Camo [ Fri Nov 11, 2011 4:46 pm ] |
| Post subject: | Re: Help! Motor issue |
Have you checked the valve lash on it yet? That's the 1st thing I'd look at since you've already cleaned the carb & changed the filter & plugs. I've several "new" motors that were way out of whack. Also, there's been a few reports of pin holes in the intake manifolds on some of the newer Briggs motors. |
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| Author: | deadbird8 [ Fri Nov 11, 2011 4:48 pm ] |
| Post subject: | Re: Help! Motor issue |
Valve lash wouldn't keep the RPM down and then let it climb. Do you have bubbles in your fuel filter when its bogging down? |
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| Author: | duckhunting84 [ Fri Nov 11, 2011 5:31 pm ] |
| Post subject: | Re: Help! Motor issue |
Thanks for the replies, I will check the valve lash. Deadbird8 I have noticed bubbles when I would run at full speed, and it never seemed to effect my rpms. How do I check the valve lash. Sorry I am new to mud motors. |
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| Author: | BoatDR [ Fri Nov 11, 2011 7:45 pm ] |
| Post subject: | Re: Help! Motor issue |
Do you have a primer bulb? If so, squeeze it when it is cutting up to see if it picks up. If not, install one and try squeezing it. That will check for a fuel pump or fuel supply problem. |
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| Author: | Duckdon [ Fri Nov 11, 2011 7:46 pm ] |
| Post subject: | Re: Help! Motor issue |
Sure sounds like carb icing. Don't know where your running or how cold it is. Anything under 45F and high humidity can cause carb icing. Turn your air intake cover so it is over your muffler if thats possible and try it. I have a 35 B&S and I run a snorkle on my intake to get the warmer air and it stops the ice up problems. Duckdon |
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| Author: | duckhunting84 [ Sat Nov 12, 2011 8:32 am ] |
| Post subject: | Re: Help! Motor issue |
Okay, so I checked the valve lash, and they were off a little. I ran the motor on the trailer last night and the adjustments I made to the valve's gave me a few more rpms. I was turning between 4200 and 4210. While running at wot, I checked for bubbles in the filter, and didn't see any. I am in Utah and it has been in the 20-30's out in the marsh when I was having problems. Boat Dr. I do have a bulb, and will try what you have mentioned. Duckdon I had turned the air intake so it is pulling warm air from the muffler, but it was still doing the same thing. We are getting a big cold front hitting us this weekend, and I dont want to get stuck out on the water in it with a motor running poorly, so I wont be able to check my performance in water till Tuesday. I will post up what I find. Thanks again for all your input. any other ideas, of what could be causing this? |
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| Author: | russellm454 [ Sat Nov 12, 2011 12:07 pm ] |
| Post subject: | Re: Help! Motor issue |
First thing that came to my mind is that it could be a loose fuel connection sucking air. Valve lash likely wouldn't cause it to run poor, then be OK and go back to running poor again. I'd check all the fuel connections and make sure the gas tank vent is open. Like was suggested when it is running poorly squeeze the fuel bulb and if it picks up you have a fuel delivery issue. I'm assuming your OOW RPM's are done under load, out of neutral. Yea I know the dangers of a spinning prop OOW but it is possible that you could have something binding in the outdrive that is bogging the motor down also. Just some thoughts, Russ |
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| Author: | duckhunting84 [ Tue Nov 15, 2011 4:46 pm ] |
| Post subject: | Re: Help! Motor issue |
Okay, so I went out today and ran the boat. I set the valve lash, I tightened all the fuel connections(no more air bubbles in the fuel filter.) So I start out with an average hunting load. The motor is running great! fastest I have had this boat run. Motor is smooth, and I think sweet its all fixed and the problem is solved. We set up, and then end up moving to a different spot later in the morning. Motor is still running great! After we are done hunting, we pick up and start back to the ramp. The motor is still running great, at about the half way point it starts cutting out a little, so I pump the fuel primmer bulb, and it doesn't help. I slow down to an ideal and am thinking what the He!! just happened. I try to get going again, and it starts back firing, and running like crap, I can't get the RPM's above 2500, and most the time not even that, before it is bogging down and back firing. We limp back to the boat ramp and trailer the boat. I pull the plugs, which are new, and gapped to .35, and one side is a nice tan color, and the other is bone white. So I know it is lean on that side, and that is where the back firing came from. So at this point, I am at a loss, is the carb my issue? Could it be my coils? I am still waiting to hear back from Mud buddy, I have left several messages, but I guess they are too busy at this point in the season to get back to me. Any help would be great. Thanks |
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| Author: | BoatDR [ Tue Nov 15, 2011 4:50 pm ] |
| Post subject: | Re: Help! Motor issue |
How old is this motor (the year model)? |
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| Author: | Beadlejuicejr [ Tue Nov 15, 2011 4:57 pm ] |
| Post subject: | Re: Help! Motor issue |
Check to see if your spark plug boot is arcing off or coming loose kinda sounds like it's comin loose after awhile of running had that happen it would start to come off and cause the motor to back fire and wouldn't get any rpms and do the samethin. Try to see if it's arcing off before anything else I would try electric taping the plug wine from the coil to the end of the boot and see what happens then |
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| Author: | duckhunting84 [ Tue Nov 15, 2011 7:02 pm ] |
| Post subject: | Re: Help! Motor issue |
Boat Dr. The motor is a 2009 sport lite 35 vangaurd. I will try the electrical tape as well. Thanks |
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| Author: | dguidry [ Tue Nov 15, 2011 9:04 pm ] |
| Post subject: | Re: Help! Motor issue |
Lawnmowers are not used in winter so icing is not a design issue. |
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| Author: | russellm454 [ Wed Nov 16, 2011 7:07 pm ] |
| Post subject: | Re: Help! Motor issue |
Is it bone stock or aftermarket carb, other add on's. Has it ever had any work done on it? If so what and did the issue start shortly after that? When you say bone white are you talking like the way a new spark plug looks when new or does it have a white powdery residew on it? This is a tough one to diagnose over the internet, especially since it ran fine for a while. Make sure those fuel connections didn't come loose or some how you are getting fuel starved. Is there any way the vent on the fuel cap could have closed up while running back to the ramp. Russ |
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| Author: | duckhunting84 [ Fri Nov 18, 2011 8:25 am ] |
| Post subject: | Re: Help! Motor issue |
It is fixed!!! After all the help you guys gave me, and some PM's with Boat Dr. I got it all fixed up yesterday. The culprit, Autolite spark plugs. Boat Dr. suggested that I take a pair of stock champions out with me, and if the motor cut out, to put the champions in. Well I did this and it fixed the problem. When I got home I gave the autolites a look over and found one of them have a small hairline crack in the ceramic outer part of the plug. So my guess is it was arching off that and the motor, or it was just damaged and not throwing a good enough spark. Thanks for all your help, this site and the people on it, are great!!! I am heading out to try to help 2 buddies fill swan tags!! If we get some down i will post up some pictures! |
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| Author: | russellm454 [ Sat Nov 19, 2011 1:00 am ] |
| Post subject: | Re: Help! Motor issue |
Good to hear that good luck with the hunt. |
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