Main Menu
Advertisement
Affiliates
Advertisement
Newest Members
Gary Roberts, Granbry, Gman.1218, Gkirk842, William Garcia
102693 Registered Users
Top Posters
TexDawg 82828
hopalong 74332
Pilothawk 73387
JDavis7873® 67377
FattyMcButterpants 60518
John175 ® 59850
Tritonman 56789
Derek 56400
SkeeterRonnie 52444
LoneStarSon® 52199
facebook
Forum Stats
102693 Members
61 Forums
858471 Topics
11261771 Posts

Max Online: 36273 @ 01/23/13 02:34 PM
Topic Options
#11738235 - 07/23/16 02:48 PM Yamaha vmax 150 - fuel problems
CoachCBA Offline
TFF Celebrity

Registered: 07/10/10
Posts: 5441
Loc: Whitehouse, TX
Motor has always run fine. Had a lower unit replaced, and while it was in the shop I had the carbs rebuilt and a hot foot installed. It has run like junk ever since. The symptoms are:

1. Will not idle. Idles extremely rough and slow and then putters out.

2. Has become very tough to start, and when I finally get it started there is a huge smoke cloud, then the smoke goes away. Have to have the throttle hammered down to get it to start and run.

3. After idling onto the trailer bunks, I give it throttle and it bogs down and shuts off. At this point after restarting it every time I mash the throttle to push it on trailer it bogs down and dies. Also, at this point, I can't back it off the trailer without the engine bogging down and dying.

4. It used to run at wot at about 5000 rpm. Now, after I get it on plane, max rpm is about 4400, then slowly fades to between 3800 and 4000. If I make a sweeping turn, it briefly goes back up to 4200 rpm then fades back down to 3800 and 4200.



I'd appreciate any and all thoughts.



Edited by CoachCBA (07/23/16 05:05 PM)
_________________________
"One can only get so stupid, then you die." - Pilothawk

Top
#11739036 - 07/24/16 07:26 AM Re: Yamaha vmax 150 - fuel problems [Re: CoachCBA]
gary purdy Online   content
TFF Guru

Registered: 05/24/03
Posts: 10512
Loc: Littlefield Tx & Lake A. H. US...
Manual fuel pump diaphragms.
_________________________
“The world will not be destroyed by those who do evil, but by those who watch them without doing anything” GOD IS GOOD

Top
#11739158 - 07/24/16 09:14 AM Re: Yamaha vmax 150 - fuel problems [Re: CoachCBA]
CoachCBA Offline
TFF Celebrity

Registered: 07/10/10
Posts: 5441
Loc: Whitehouse, TX


do you mean these pumps?
_________________________
"One can only get so stupid, then you die." - Pilothawk

Top
#11739172 - 07/24/16 09:25 AM Re: Yamaha vmax 150 - fuel problems [Re: CoachCBA]
CoachCBA Offline
TFF Celebrity

Registered: 07/10/10
Posts: 5441
Loc: Whitehouse, TX
Or do you mean the bulb between the tank and the motor?
_________________________
"One can only get so stupid, then you die." - Pilothawk

Top
#11739631 - 07/24/16 03:03 PM Re: Yamaha vmax 150 - fuel problems [Re: CoachCBA]
gary purdy Online   content
TFF Guru

Registered: 05/24/03
Posts: 10512
Loc: Littlefield Tx & Lake A. H. US...
The arrows point to the manual fuel pumps or low pressure fuel pumps. The diaphragms are a known yamaha problem. They rebuilt the carbs on this motor in the picture?
_________________________
“The world will not be destroyed by those who do evil, but by those who watch them without doing anything” GOD IS GOOD

Top
#11739677 - 07/24/16 03:43 PM Re: Yamaha vmax 150 - fuel problems [Re: gary purdy]
CoachCBA Offline
TFF Celebrity

Registered: 07/10/10
Posts: 5441
Loc: Whitehouse, TX
Originally Posted By: gary purdy
The arrows point to the manual fuel pumps or low pressure fuel pumps. The diaphragms are a known yamaha problem. They rebuilt the carbs on this motor in the picture?


No, I found this picture online. I'll see if I can change these and see if it helps.
_________________________
"One can only get so stupid, then you die." - Pilothawk

Top
#11742123 - 07/25/16 09:06 PM Re: Yamaha vmax 150 - fuel problems [Re: CoachCBA]
Stump jumper Offline
TFF Celebrity

Registered: 04/19/04
Posts: 6983
Loc: Rockwall
Take it back to the shop that did work. I had carbs on Merc rebuilt once a got some bad needles. Before mechanic replaced them he made me replace all the fuel lines. You could have bad fuel lines flaking on inside. If so you will chase your tail tearing down carbs.

Top
#11743626 - 07/26/16 05:48 PM Re: Yamaha vmax 150 - fuel problems [Re: CoachCBA]
blackhorse Offline
Outdoorsman

Registered: 05/13/08
Posts: 113
Loc: Morgan, Tx
What year is your engine?

Top
#11743993 - 07/26/16 09:08 PM Re: Yamaha vmax 150 - fuel problems [Re: blackhorse]
CoachCBA Offline
TFF Celebrity

Registered: 07/10/10
Posts: 5441
Loc: Whitehouse, TX
Originally Posted By: blackhorse
What year is your engine?


2006.
_________________________
"One can only get so stupid, then you die." - Pilothawk

Top
#11773959 - 08/12/16 06:02 PM Re: Yamaha vmax 150 - fuel problems [Re: CoachCBA]
CoachCBA Offline
TFF Celebrity

Registered: 07/10/10
Posts: 5441
Loc: Whitehouse, TX
Update:
Turns out the shop that did the original work did not change the plugs, which were fouled. Service Marine in Emory changed em, synced the carbs and adjusted the idle and it runs like a top now.

Should have gone to Service Marine the first time.
_________________________
"One can only get so stupid, then you die." - Pilothawk

Top



© 1998-2016 OUTDOOR SITES NETWORK all rights reserved USA and Worldwide