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waterfowler817
MMT Member
Joined: Wed Nov 28, 2012 10:44 am Posts: 25
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 36hp Briggs - Low RPM's under Load
I have a 2009 PD. Governer set at 4450 and valves gapped to .0025. At correct prop height will only turn 3400 RPM's with just me in boat at 24MPH max. Boat is a 1854 WC.
Am looking to have valves seated and cam checked by valve movement tomorrow. Any other common problems that I need to look at to get my RPM's up to 3900 range?
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Thu Dec 19, 2013 3:28 pm |
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diddyduck
MMT 1000 Club
Joined: Mon Sep 02, 2013 10:24 pm Posts: 2624 Location: ponchatoula, la
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 Re: 36hp Briggs - Low RPM's under Load
valve lash is set at .0025???
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Thu Dec 19, 2013 3:34 pm |
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banded-mallard
MMT 1000 Club
Joined: Wed Oct 07, 2009 8:18 pm Posts: 4310
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 Re: 36hp Briggs - Low RPM's under Load
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Thu Dec 19, 2013 3:35 pm |
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diddyduck
MMT 1000 Club
Joined: Mon Sep 02, 2013 10:24 pm Posts: 2624 Location: ponchatoula, la
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 Re: 36hp Briggs - Low RPM's under Load
supposed to be set between .004-.006 i set mine at .005
may be part of your issue
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Thu Dec 19, 2013 3:37 pm |
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Jamie B.
MMT 1000 Club
Joined: Tue May 19, 2009 9:48 am Posts: 2688
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 Re: 36hp Briggs - Low RPM's under Load
^^^^^ Yes that would be between .004 and .006.lol
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Thu Dec 19, 2013 4:45 pm |
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Will
MMT Elite Member
Joined: Fri Jul 08, 2011 1:54 pm Posts: 8133
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 Re: 36hp Briggs - Low RPM's under Load
That's as tight as Dick's hatband!
Sent from my iPhone using
_________________ Before the internet, the majority of the village idiots stayed in their villages.
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Thu Dec 19, 2013 5:07 pm |
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banded-mallard
MMT 1000 Club
Joined: Wed Oct 07, 2009 8:18 pm Posts: 4310
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 Re: 36hp Briggs - Low RPM's under Load
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Thu Dec 19, 2013 7:56 pm |
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diddyduck
MMT 1000 Club
Joined: Mon Sep 02, 2013 10:24 pm Posts: 2624 Location: ponchatoula, la
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 Re: 36hp Briggs - Low RPM's under Load
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Thu Dec 19, 2013 11:24 pm |
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Gray Goose
MMT Pro Member
Joined: Tue Feb 14, 2012 2:17 pm Posts: 141
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 Re: 36hp Briggs - Low RPM's under Load
Shit, .0025 you might be floating the valves from having no lash.
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Fri Dec 20, 2013 10:04 am |
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waterfowler817
MMT Member
Joined: Wed Nov 28, 2012 10:44 am Posts: 25
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 Re: 36hp Briggs - Low RPM's under Load
I thought that was a little to tight also, but Prodrive told me .002-.003...
Took it in today for a leakdown test. Both of the intake valves need to be replaced. It wouldnt hold more than 25 psi before blowing back out the carb and that was with the valve covers off and both of the rockers loose.
Ordered the parts from Briggs and should be here next week. Have never installed lapping compound so looks like I have a few videos to watch...
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Fri Dec 20, 2013 5:26 pm |
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waterfowler817
MMT Member
Joined: Wed Nov 28, 2012 10:44 am Posts: 25
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 Re: 36hp Briggs - Low RPM's under Load
Got my heads torn apart and you wouldn't believe how bad my intake valves were. Still attached to the spring I could slide multiple playing cards around 3/4 of each intake valve. The picture below is of the intake valve completely seated and a light in the head port.
Got the new valves seated correctly and installed. I am hoping that this will make a night and day difference with my low RPM's and load carrying issues. I bet these have been this way since I purchased this motor... I was in shock that it would even run at all with valves that bad.
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Mon Dec 30, 2013 4:30 pm |
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Will
MMT Elite Member
Joined: Fri Jul 08, 2011 1:54 pm Posts: 8133
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 Re: 36hp Briggs - Low RPM's under Load
Briggs man, they all get like that. You should see a big difference and they'll last longer no that the heads are seasoned.
_________________ Before the internet, the majority of the village idiots stayed in their villages.
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Mon Dec 30, 2013 5:49 pm |
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