Thread: GP1200R Problem
04-28-2009, 09:39 AM #1
What would cause a newly rebuilt motor to run pretty well overall, have good compression, start ok, idle well after starting, but die at idle after being run at operating temps? Am I looking at a seizure?
Carbs check out, it's pre-mix... I had a fuel delivery issue but I worked it out.. Is it possible that the fuel problem gave it a light seizure? I will be pulling the heads soon.
04-28-2009, 10:23 AM #2
How long does it take before it dies? It could be a fuel pump problem; a stuck needle/seat; an improperly set idle mixture. Hard to tell from what you've told us. Does it restart easily after dying? Are you seeing declining rpm's before it dies?
I doubt you're having a lean seizure at such low rpm, but you'll have to pull the heads to see.
04-28-2009, 10:34 AM #3
It will run all day if it's got throttle...It takes me 10 minutes to no wake out to the lake.. No problems there.. I will run it, no problems there... Once I get it warm, and get off the throttle, it dies. Starts right back up... I can give it gas and it will go, but once it's warm it dies at idle. Once it cools off, it's fine again and the cycle starts over.
Heads come off this week.
04-28-2009, 10:53 AM #4
Have you set the idle rpm properly? Did you check popoff pressure and low speed mixture screws?
04-28-2009, 01:14 PM #5
I did bench test the carbs after cleaned and rebuilt them. I followed the steps from the carb application I got from this site. Now with that said, I was having a fuel issue and I may have changes the settings a bit.. BUt I woudl have gone rich not lean. Could it be a "too rich" condition on the low end circuit?
04-28-2009, 01:19 PM #6
Man, you're killing me. I don't know what "bench test" means to you, so I still don't know if you checked popoff, low speed screws, idle screw setting, synchronized the carbs, etc.
What is this "fuel issue" you keep referring to? What "changes" did you make after the "fuel issue" to make it rich? You're not going to get much help if you don't elaborate. I'm trying to help.
04-28-2009, 02:09 PM #7
Sorry FullBoogie... I will elaborate..
I rebuilt the top end of my motor(pressure tested per Fercho) and rebuilt the carbs. I cleaned off all the calcium? spots from the internal carb bodies and replaced some rubber gaskets and those little circular plastic diaphragms(one was creased). I followed all the instructions for pressure and pop off testing as well as syncing the carbs, checked needle and seats, springs, and made sure the armature was working in unison and opening properly. I set the high speed screws to 1.5 turns and the lows to 1 turns out (carbs were cleaned along with the t-handles so I know they were seating properly)
As for the fuel issue, my primer was bad, so it was sucking air. It would prime the engine fine, but after riding a bit the engine would quit. I noticed that one of the fuel lines would have air pockets in it (they are clear lines, I am using a dual pickup setup) I traced the issue back to the primer (had to destroy the thing to find it) and replace it. The fuel issues went away, but now I am faced with this one.
I have run the carb t-handles on the high side from 1.25 turns out to 2.5 turns out. On the lows from 1 turn to 2 turns... And everywhere in between.
I am not getting anywhere. It seems to do better richer, but then I am cleaning plugs all the time.
04-28-2009, 02:12 PM #8
Have you looked at the tank venting system??
04-28-2009, 02:28 PM #9
Yep.. Clear and functioning..
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By ericheavner in forum Yamaha How To & FAQsReplies: 8Last Post: 08-15-2008, 09:35 PM
By ckassen in forum Yamaha PWC Performance (2-stroke)Replies: 10Last Post: 07-20-2008, 02:46 PM
By YOUNGGUNZ403 in forum Yamaha PWC Performance (2-stroke)Replies: 18Last Post: 06-19-2008, 11:59 PM
By jbgpr in forum Yamaha PWC Performance (2-stroke)Replies: 15Last Post: 03-26-2007, 12:09 AM
By ramnj in forum Yamaha PWC Performance (2-stroke)Replies: 47Last Post: 06-05-2006, 08:57 AM