2004 50 hp T50TLRC starting problems

[Fishhauler]

Some background: problems with carbs. Removed carbs disassembled cleaned them with BERRYMAN Chem Dip. Replaced gaskets when reassembled. Synchronized carbs. Motor ran best it ever did. Started motor every Saturday for about 2 months. No problems. Was away for about a month working on a job. Came home and motor will not start. Replaced plugs, checked spark. Spark good but will not start. Checked fuel pump and it works. Turns over good but just won't start. Every now and then acts like it wants to start. Any help would be appreciated. I also checked safety kill switch and have continuity with clip in. Also put in fresh gas (nonethanol) I will put in marine stabilizer when it runs.

[boscoe99]

Mist a bit of gasoline into the intake screen when cranking the motor. If it starts up and runs, however briefly, then I am betting that the carbs are fouled up.

If you look at the parts book for your motor a #39 idle jet is used. Earlier models used a #42 jet. If it were my motor I would go back to the #42 jets. Or larger. It might use ever so slight an amount of additional gasoline but it will improve the startability and idleability of the motor.

[TownsendsFJR1300]

Plus one on the carbs being varnished up again. Fuel goes bad in as quick as a month.

Even of you run the engine dry, a little remains in the float bowl to varnish shut the main/idle jets..

IF, your going to leave the engine for a length of time, simply drain the bowls with the drain bolt on the bottom of the bowl(s).


Also, once its running again, use Yamaha's RingFree. Works very well at keeping at the fuel system clean and top end. Obviously, a stabilizer is needed. Gas Shok works very, very well IME..

[Fishhauler]

Thank you for the replays. I went out and tried to mist some gas into the breather. Took a few tries but finally did get a little pop like it was trying to start. On my day off tomorrow I will disassemble the carbs again, clean and blow them down. I also think I will order some bigger jets. I will make another reply after the carbs are clean. Thanks again to both of you for your help.

[Fishhauler]

Ok I cleaned carbs and found they were a bit gumed up. I tried to start after cleaning and still not wanting to run. Pulled plugs and no evidence of fuel getting to the cylinders. Fuel seems to be coming out of breather after cranking for awhile. Frustrated and can't believe it won't start. Who's got an idea what to do now.

[TownsendsFJR1300]

Pull the drain plug (with the carbs still attached) and see if your getting fuel to the carbs/bowls. It possible a float may be stuck.

With the drain bolt out, prime the bulb and see if you get fuel coming out. Make sure the bulb itself (the imprinted arrow) points up at least initially when priming, it does make a difference..

I'm assuming the needle / float IS assembled correctly.


Did you actually pull the main, idle, other jets and physically look thru them?
A simple chemical bath may have not cleaned them fully.

You have to be able to see thru all the jet orifices

[Fishhauler]

Yes when I cleaned the carbs I removed the main and idle jets and looked thru the Jets and could see light come thru. I used my compressor and a blow gun to push air thru all ports. When reassembling the carbs I made sure the floats were free and were set to the proper height. After I tried to start I also removed the carb bowl drain plug on the top carb and gas drained out. I also went back and checked for loose wire connections and found none. Looked at timing belt and it looks to be good with no evidence of it jumping time. When it stops raining I will go back out and check the other three carbs for gas in the bowls.

[rodbolt17]

did you replace the oring around the main jet plug.
did you test the enrichment valves for proper operation?

if you suspect its lean take a rag and block off the air intake at the bottom of the air box and crank it.

you will NEED, MUST USE, a 4 channel manometer to properly resync the carbs.
no way around that part.
did you drill out and remove the A/F cover plugs?

[Fishhauler]

No I did not replace the o-rings on the main jet plug. They seem to be good. Are you talking about the prime start valves as the enrichment valves. If so I looked at them and tested them. One of hem didn't move at all when connected to 12 v. I purchased new one and installed. Did that when problem started. The other one moves but not a lot, but it moves. Slightly under spec. Are you referring to air filter plugs by A/F plugs? No I did not open air filter housing. I looked at it but did not open it because it looked like it is factory sealed. It looks like if separated it would need to be re-glued. I did look inside best I could through the opening. Didn't see much. Thought this was strange as air filter is one thing I always look at when working on small engines. Do you think I should remove and inspect? If so I will replace the o-rings on the main jets. Getting good at removing the carbs by now and shouldn't take long. Lol

Do you think I need to re sync the carbs. I have not touched the adjustments?

[99yam40]

A/F cover plugs he is referring to should be the covers/plugs that keep people from messing with the air to fuel pilot/idle screws.

carbs need to be re synced every time the carbs are reinstalled

[rodbolt17]

from the factory the air/fuel mix screws had a brass plug over them. ty[pically I use a 9/32 bit ,drill a hole trying not to let the bit hit the A/F screw and then use a #10 self tapping screw and pliers to remove them.

if the main jet oring gets hard and cracked that motor runs like cwrap.

quite often you can block the airbox opening at the bottom and force it rich to make it run while you attempt to adjust it.

[Fishhauler]

No I did not drill out the air to fuel mixture plugs. When rain quits I am going to try and put rag over intake and see what happens. I will then connect manometer and check carb sync.

[rodbolt17]

has to be a 4 channel. you have to adjust all 4.
well actually 3.
set the engine speed at 1100 RPM using the idle screw on #4.
then set 1,2 and 3 at the same Hg as 4.
remember as you get closer you will have to readjust the setting speed to 1100 RPM.
that's why a 4 channel manometer is required.
as you start changing 1,2 and 3 you will see 4 change and the idle speed change.

[throrope]

I suggest checking the fuel supply upstream of the carbs all the way to and including the tank. I went through my carbs and undid my work with the next trip due to contaminated gas and ethanol rotted lines. The stuff is nasty.

I now make a habit of emptying the boat including carb bowls of all fuel between trips. I also replaced the fuel line with 3/8" copper save a few feet to the tank and motor. This lets me renew the remaining hose every year in ten minutes for ten bucks.

[boscoe99]

If the idle mixture screw was not removed the carburetor was not properly cleaned IMO. Back to the drawing boards.

Do youngsters even know what a drawing board is?