PDA

See full version: Yamaha 50hp outboard only running on 2 cylinders


bitcoinuser
29.04.2021 4:50:36

LIT-18616-01-79 Service Repair Manual Application: 1998-2005 Yamaha Marine Outboard 4HP (4-HP) 4-Stroke Engines F4X (F4-X, F-4X) 1999, 2000, 2001, 2002, 2003, 2004 & 2005. This manual covers all 4HP 4-Stroke models world wide including F4MSHX, F4MLHX, F4AMH, USA CANADA.


sleasalo
12.06.2021 12:41:18

See Starting & Charging System Troubleshooting in Service Manual. [links]


fulong829
16.06.2021 7:00:01

LIT-18616-01-28 Service Repair Manual Application: 1995, 1996, 1997 (95, 96, 97) Yamaha Marine Outboard E48T (E48-T) C55T (C55-T) 48HP & 55HP 2-Stroke. Item Model Names: E48T, C55T, E48C, E48MH, E55C, 55BM, C55ER, 55BE, 55BEM, C55TR, 55BET.


yuone
10.05.2021 3:12:05

LIT-18616-02-66 Service Repair Manual Application: 2004 2005 2006 Yamaha Marine Outboard 70HP (70-HP) 2-Stroke Engines. Model name 70BETO, USA and Canada name 70TR 70C (70-C).


Nerd
11.05.2021 8:45:25

Throttle is “rolled back” or closed, thereby actuating idle cable roll-off (disengage) switch.


Kline
25.04.2021 2:00:06

FUEL SYSTEM TROUBLESHOOTING


Xaxo
29.04.2021 4:50:36

I wouldn’t be surprised if it was the inner exhaust plate. Salt water motor? Not flushed after use?


ankostis
12.06.2021 12:41:18

Getting closer I will post pics 2 morrow once they go to the icloud. 2 screw heads were missing on the top cylinder reed valves closest to the rod the 3rd and only screw left was barely holding the reeds and back stop on the screw being bent kept it from unscrewing. My bet is the rod knocked the screw heads off. Here is an auction on ebay right now for a used reed valve assy for that motor notice how the middle screw has been getting hit by the rod. http://www.ebay.com/itm/381402128198?_t … EBIDX%3AIT leads me to think it is a problem with these motors especially when compression is over 170 on each cylinder. [links]


jcw9
16.06.2021 7:00:01

I put a used rod on the upper cylinder when I rebuilt it due to cost of new one which was in specs with a new big rod bearing assy. It is possible when it threw the rod it loosened those screws since the rod cap bolts had loosened causing the engine failure and they unscrewed and the rod hit them I didn’t notice that when I had it apart. I felt the rod with my finger where the two halves of rod come together it still feels tight. I decided to roll the dice and fixed the reed assy best I could and added new screws and lock washers re-installed it and the motor ran a lot better almost getting to WOT. I am going to pull them back out 2 morrow and see if the rod has pecked on the new screws if so the motor will have to come back apart and I haven’t wasted my new head gasket that is coming if not I will look for some good used reeds assy.


adamjkok
22.05.2021 12:34:45

Post by nccatfisher » 04 Feb 2020, 16:40 here


cronicleu1
23.05.2021 16:25:02

Post by Riverdog » 04 Feb 2020, 20:00 here


Dae
24.04.2021 5:44:26

I'm looking at a 98 Johnson 50 hp SPL 2 cylinder outboard motor ,my plan was to put a jet pump on it .
I have no experience with this motor so any info would be greatly appreciated .
I have a factory 40/30 yamaha jet on a 1448 MV Lowe currently am I better off with the Yamaha motor instead of the Johnson ?
thanks folks


mtp
06.06.2021 2:44:13

Post by nccatfisher » 04 Feb 2020, 23:24 [links]


tamara
25.05.2021 21:50:27

2013 1752 Blazer SS Mercury 60/40 here


protein87
11.05.2021 21:19:53

Modern fuel systems on outboard engines are complex. In the old days, fuel was delivered to the engine in a gravity-feed system, but that is no longer the case. [links]


lanpeck5
18.06.2021 18:24:46

Yamaha outboards are also quieter than most other brands, again in particular comparison to Honda. Outboards are loud, period, but Yamaha’s 40 is will be easier to hold a conversation over. here


KristofN1
25.05.2021 18:03:34

Several models of the 4-stroke 40 using carburetors from before 2010 had particular difficulty gumming up, and the design made it difficult to clean them. Replacing them was the only option, and the difficulty in this design-led to most of the 4-stroke 40s going to fuel injection. [links]


happyrock
19.06.2021 5:18:06

This makes it a little bit easier to deal with maintenance. more