Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

[dano777]

I recently pulled the carbs off for a thorough cleaning for the first time. ( I just got the boat a week ago) I made careful notation of linkage / needle adjustments etc during disassembly. What I didn't notice was there was a difference on the main jet stampings, half are 160# and the other 3 are 168#. I assume at this point that the engine has been overhauled and half the cylinders have over-sized slugs in them. Through the chem-dip processing, I have no idea which side of the carb the 160 goes and which side gets the 168. (blame it on the fumes I guess, I should have known better)

I didn't know it had been gone through or I would have checked it closer. I am assuming it lost cooling on one bank and cooked things at some point.
Is there any way to tell which side needs the larger jet or is this all normal and one side always gets a larger jet and/or different needle settings as I have seen in other posts. What is the proper baseline of the needle settings for this anyway? Amazon is out of the manual for these older engines.

Thanks in advance.
Dan

Anyway the teardown was for extremely poor idle that improved with addition of choke. Top end was great. Inspection of bowls showed some varnish - 1 year since a shop did the carbs, mostly clean, looks like they missed cleaning everything completely as some of the buildup was far older than most. Half of the idle feeds of the bowls were clogged, mains were clean.

 

[rodbolt]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

go to the yamaha parts website.
pray they show the jets.
but yes from the factory your engine was jetted different from port to stbd.
hopefully Ray Nuedecker will see this, he is a bit older and wiser and may actually remember which side is which.

 

[dano777]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

Rodbolt,

Thanks for that, I just checked the exploded view and it shows #160 starboard and #168 port. If I can trust that I guess I'm golden now.

I'm still scratching my head as to why one side would be different from the other.

 

[robert graham]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

probably the same unknown and mysterious reason my 90C Yamaha has a slightly different compression ratio in all 3 cylinders. If you find out about the difference in your jet sizes please let us know. Good Luck!

 

[dano777]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

The boat absolutely screams now and has a smooth idle down to 5-600 RPM. I was out only the time and half dozen o-rings.

Cleaned 18 white bass for my effort last night.

good fishing all!! Thanks for the help.

Dan

 

[rodbolt]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

carbs point to the front,also known as the bow. the heads are aft also known as the stern.
port is ALWAYS port and STARBOARD is ALWAYS starboard reguardless of if your behind the monitor or on the dock or upside down under the console.

 

[BigNiner19]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

I believe this is the same motor I have, and I MAY have mixed the jets up when putting back together myself. Now I cant even get my motor started, so I doubt the jets have anything to do with it, but this is interesting, as I just read in the manual that there are "port" and "starboard" jets and the engine can be harmed if installed in the wrong one.

Anyone have a better explanation to this?? There's no way that this could be keeping my motor from firing up could it???

Cory

 

[MID FL CAP]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

if you had your carbs off ,did you do the "link and sync"? that is very important!

 

[BigNiner19]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

Could someone explain what link and sync needs to be done. I didnt mess with the bends on any of the tangs or the throttle arms or anything. Would the link and sync for the carbs keep the motor from starting?

I go through two seperate manuals and the only Link and Sync relating to the carbs is how to measure the floats from the gasket (16mm)

Cory

 

[pine island fred]

Re: Yamaha '89 225 excel with mixed main jets #160 and #168 normal ?

Go to yamahaoutboardparts.com the guru that you need is there.