User Tag List

Page 1 of 2 1 2 LastLast
Results 1 to 15 of 16
  1. #1
    Join Date
    Mar 2018
    Location
    Boise, Idaho
    Posts
    16
    Thanks (Given)
    3
    Thanks (Received)
    0
    Likes (Given)
    2
    Likes (Received)
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    2001 Merc XR6 150hp low on power (Resolved)

    This weekend I found my xr6 is low on power. The top speed is down by 25% and it is slow coming out of the hole. Compression is very close to 120 all around. Fuel pump was rebuilt just a few months ago. The only clue I have to go on is that the all new spark plugs show normal coloration on the 4 bottom cylinders. The ground electrodes are dark grey with dark oily residue on the threads. In contrast, the top cylinder on each side has plugs that look like brand new, only a very light film of fuel. It doesn't look like they have seen any combustion byproducts at all. The electrodes look pristine.
    Today I started it up on the garden hose and ran it for probably 30 seconds. Afterwards, I removed the spark plugs, and exhaust smoke was curling out of the holes. All the spark plug holes had similar exhaust exiting, so it seems like maybe there is combustion happening it to top cylinders. Top plugs still look shiny new. While it was running, I blocked airflow into the carbs with my hand and the vacuum seems similar between top and mid cylinders. Doing this causes fuel to spit into the carb throats, but I could see no difference in behavior between top and mid cylinders.
    I do run a jet pump on the xr6, and I started having problems when I plugged up the jet when I ran over some weeds. When the jet clogs, it can cause the motor to rev. Could this cause a carb issue, or maybe cause problems with the reeds? I'm not sure what to try. Should I rebuild the top carb?

    -Cliff
    There was fuel in the top-carb float bowl when I removed the bowl plug.
    Last edited by Desert_Howler; 10-02-2018 at 02:50 PM.

  2. #2
    Join Date
    Sep 2017
    Location
    Ashland city tn
    Posts
    3,722
    Thanks (Given)
    153
    Thanks (Received)
    264
    Likes (Given)
    660
    Likes (Received)
    729
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Do you have a over loading carb? Will be leaking gas out front of that carb?

  3. #3
    Join Date
    Mar 2018
    Location
    Boise, Idaho
    Posts
    16
    Thanks (Given)
    3
    Thanks (Received)
    0
    Likes (Given)
    2
    Likes (Received)
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    No, not leaking gas.

  4. #4
    Join Date
    Dec 2012
    Location
    tn
    Posts
    687
    Thanks (Given)
    8
    Thanks (Received)
    17
    Likes (Given)
    5
    Likes (Received)
    46
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Would seen #1 & #2 are not firing. Suggest you start on hose again and pull plug wires while running on 1 & 2 and look for spark. Also let it run for a few minutes and see if 1 & 2 plugs get warm/hot to the touch. Another thing that will clean plugs is water in the cylinders.......

  5. Thanks Desert_Howler thanked for this post
  6. #5
    Join Date
    Mar 2018
    Location
    Boise, Idaho
    Posts
    16
    Thanks (Given)
    3
    Thanks (Received)
    0
    Likes (Given)
    2
    Likes (Received)
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I checked for spark, and all plugs are firing. I'm leaning towards carbs since those two cylinders share the top carb. I don't know of any ignition parts that are shared between pairs of cylinders. Do you know of any?

  7. #6
    Join Date
    Dec 2012
    Location
    tn
    Posts
    687
    Thanks (Given)
    8
    Thanks (Received)
    17
    Likes (Given)
    5
    Likes (Received)
    46
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Cylinders 1 and 2 do share a carb bowl. Could be no fuel getting into carb bowl which would shut down both holes. There is a brass hex head screw on each side of the carbs - the starter side is easier to get to- with primer bulb pumped up, motor not running, remove the brass hex screw from either side, fuel should flood out. You might want to stick a rag underneath. No fuel would be stuck needle valve.

  8. #7
    Join Date
    Mar 2018
    Location
    Boise, Idaho
    Posts
    16
    Thanks (Given)
    3
    Thanks (Received)
    0
    Likes (Given)
    2
    Likes (Received)
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Hmm, carb bowl had quite a bit of fuel when I opened the brass drain plug. I removed and blew out both main jets, but they seemed clear.

  9. #8
    Join Date
    Oct 2008
    Location
    Plainville, CT
    Posts
    527
    Thanks (Given)
    248
    Thanks (Received)
    9
    Likes (Given)
    223
    Likes (Received)
    29
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Does it seem like no fuel getting to #1 an #2 or are they flooding out?

  10. #9
    Join Date
    Sep 2017
    Location
    Ashland city tn
    Posts
    3,722
    Thanks (Given)
    153
    Thanks (Received)
    264
    Likes (Given)
    660
    Likes (Received)
    729
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    #1 and 2 run off different switch boxes so I would say carb. Take off top carb,clean again , one those ultra sonic cleaners would b nice

  11. #10
    Join Date
    Feb 2014
    Location
    Missouri
    Posts
    1,171
    Thanks (Given)
    2
    Thanks (Received)
    61
    Likes (Given)
    12
    Likes (Received)
    78
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Flash light the reeds, might have bent one when the jet plugged. I would expect a weez or air sound though. Camera the piston as well before chasing your tail if plug and piston tops clean then chase fuel.

  12. #11
    Join Date
    Mar 2018
    Location
    Boise, Idaho
    Posts
    16
    Thanks (Given)
    3
    Thanks (Received)
    0
    Likes (Given)
    2
    Likes (Received)
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    @ Glastron: It kinda seems like they're not getting fuel. I would expect the plugs would look wetter if they were flooding out.

    Ok, thanks guys! I'll clean the carbs and look at the reeds. Reeds makes a lot of sense to me right now. I'll borrow a camera and take a look at the piston tops too. Thanks again.

  13. #12
    Join Date
    Oct 2008
    Location
    Plainville, CT
    Posts
    527
    Thanks (Given)
    248
    Thanks (Received)
    9
    Likes (Given)
    223
    Likes (Received)
    29
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Desert_Howler View Post
    @ Glastron: It kinda seems like they're not getting fuel. I would expect the plugs would look wetter if they were flooding out.

    Ok, thanks guys! I'll clean the carbs and look at the reeds. Reeds makes a lot of sense to me right now. I'll borrow a camera and take a look at the piston tops too. Thanks again.
    Reason I ask is that in either case it won't run good, but I'm not sure what the plugs would look like in both cases. Seems the only common point for those two cylinders is the carb. One time the valve seat was leaky on one of mine, but then the bulb wouldn't get hard when pumped and gas leaked all over. I imagine your bulb does get hard then.

  14. Thanks Desert_Howler thanked for this post
  15. #13
    Join Date
    Mar 2018
    Location
    Boise, Idaho
    Posts
    16
    Thanks (Given)
    3
    Thanks (Received)
    0
    Likes (Given)
    2
    Likes (Received)
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Found the problem.
    The needle seat had backed out. I'd never seen that before. Thanks for all the suggestions. Taking it to the river tomorrow for a test run.
    Yeah, the bulb pumped up hard.
    -Cliff

  16. #14
    Join Date
    Oct 2008
    Location
    Plainville, CT
    Posts
    527
    Thanks (Given)
    248
    Thanks (Received)
    9
    Likes (Given)
    223
    Likes (Received)
    29
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Desert_Howler View Post
    Found the problem.
    The needle seat had backed out. I'd never seen that before. Thanks for all the suggestions. Taking it to the river tomorrow for a test run.
    Yeah, the bulb pumped up hard.
    -Cliff
    Very cool. Good luck.

  17. #15
    Join Date
    Sep 2017
    Location
    Ashland city tn
    Posts
    3,722
    Thanks (Given)
    153
    Thanks (Received)
    264
    Likes (Given)
    660
    Likes (Received)
    729
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Ya that should do it,. Give her hell and gud luck

Page 1 of 2 1 2 LastLast

Similar Threads

  1. Mercury Tech: 2001 Merc XR6 150hp midrange jetting
    By Desert_Howler in forum Technical Discussion
    Replies: 13
    Last Post: 04-02-2018, 09:31 AM
  2. 2001 Mercury 150hp XR6
    By Great East Predictor in forum Outboard Engines
    Replies: 12
    Last Post: 09-12-2017, 02:50 PM
  3. 2.5 crank, 2001 150hp with rods
    By CircleHook in forum Misc. Parts and Accessories
    Replies: 2
    Last Post: 09-14-2016, 07:51 AM
  4. 2001 150hp EFI Mariner (more power?)
    By b paul in forum Technical Discussion
    Replies: 2
    Last Post: 05-27-2003, 10:05 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Chris Carson's Marine