1997 yamaha 200 hp fuel problem-This is a good one

[brico]

Dual engines engine #1 starts up fine but will only run if I keep choking it or throttle up in nuetral ( if I don't throttle or choke it will idle down to about 400 or 500 rpm's and cough and quit). Engine shut down when I put it in gear also. First noticed a problem when engine became difficult to start and then started cavitating, then this idle problem started. I did the carb kit (found a few clogged injectors and re-assembled) plugs seemed very wet and looked oily with carbon flakes. Eliminated fuel restriction and primer ball by swapping over to Engine #2 and Engine #2 ran fine with primer ball from #1 and Engine #1 still had same issues. Took fuel pumps apart (blew and sucked) seemed to be restricted when I sucked and flowed when I blew and no visible tears in gasket. Lots of particles in my fuel seperator with what looked and smelled like red wine. Thas as far as I got. need some direction. Help Rodbolt or Ray

 

[rodbolt]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

this one is incredibly simple.
rebuild your carbs using new gaskets and carefully cleaning them, no injectors, then replace the fuel pumps.
install a 10 micron water seperator and have the fuel tanks pumped of the nasties.
then go play and have fun.
fail to follow the advice and we can post all summer about a myriad of stuff

 

[brico]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

Rodbolt, I already rebuilt the carbs with gaskets and the factory kit all Three and blew out with compressed air ( carbs were incredibly clean including the needles and floats. I have a fuel seperator do you recommend replacing that with a 10 micron or adding an additional one along side the one I have now. As for the tanks is that something I can do myself (if so what is the best approach) and do you think the fuel additive i used had anything to do with this (marvel mystery)

 

[rodbolt]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

dunno about the snake oil, never tried it, simply no reason to.
DO NOT try to pull fuel through 2 water seperators, wont work.
whats the part number of the element your currently running?
guess what?
your still describing water/debris in the carbs.
watched a tech 2 weeks ago spend 5 hours doing the carbs on an F50, he hooked back up to the customers portable tank and promptly refilled the carbs with trash.
another Guess? next morning the tech was removing the carbs again.
blown pump diaphrams will cause a lean carb condition and a few cylinders will run very rich.
the cough you describe tells us the air/fuel mix is lean in one or more cylinders.
try the carbs again paying close attention to the pilot fuel and air jets.

 

[brico]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

seperator is a racor 3213, The carb kit is#64D-W0093-00 did that today and seemed a little more steady than before like it took longer for it to cough, spit and quit. The only thing I didn't do (shame on me) was the large brass screws on the top of the carbs (I just couldn't get those SOB's loose- I know go easy on me for that) the racor had debris but the filter on the motor was clean I forgot to mention that. I poke all the jets to make sure they were clear before I assembled (3) were clogged and I don't know the technical term for it but I think it was an air jet that was also clogged ( I beleive that was in the float bowl and I had to uncrew it to unclog it)

 

[brico]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

Idn't replace the plugs and gasket and I beleive a pilot air jet was clogged to follow up with the proper technical term

 

[brico]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

one more thing after reading another post a while ago. I did noticed once I lifted the engine out of the water once the water started draining from the lower unit it seemed to be a fuel slick dripping slowly from the skeg. don't know if that helps

 

[rodbolt]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

the pilot fuel jets are the 6 little tiny ones, the jet as well as the fuel bowl passage to them. the main jets are the six that are mounted horizontally in the fuel bowls.
the pilot air jets are located at the top fwd end of the carb venturi.
nothing really under those large brass scews other than some holes.
if your positive the carbs are ok and both pump diaphrams are good then check the recirc check valves on the block for each cylinder.its a pain but if they blow out it causes plug fouling and general poor idling.

 

[brico]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

Rodbolt, took fuel pumps off again and low an behold I found a tear in one, replaced it and now the engine on start up jacks up the rpms and then settles down. However I think i have a fuel restriction as well in my primer ball because it is not staying hard and as it softens the rpms come down and then engine eventually shuts off due to fuel restriction (I think) I am going to replace the ball and give update. Thanks again for your help. PS is it normal for carbs to puddle in and around the jets

 

[brico]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

Replaced primer ball, but no luck. It is still shutting down at 500 rpm but can keep running just by hitting the keyswitch choke every 20 seconds or so. Should I revisit the carbs again or go with check the recirc check valves which I have no idea where they are and I didn't see them in the clymers service manual. Any ideas

 

[brico]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

I forgot to mention that I can put it in gear now without it shutting down

 

[brico]

Re: 1997 yamaha 200 hp fuel problem-This is a good one

well I took the carbs apart again cleaned every Jet, air hole, nook and cranny. I even shined a flashlight through the holes. I am pretty sure carb#1 had another clogged jet. Idling much better now after adjusting the idle screw(was idling in the 9's and 10's brought it down to about 7). RPM's jump to about 1600 or 1700 when I first fire it up (not sure if that normal or not cause Engine #2 only goes to about 1200)So in conclusion I think it was a combination of clogged jets and air pilot holes (I either missed a jet the first time or it debris ran through a second time) along with a bad fuel pump. Engine when I throttle up in neutral is very smooth and responsive unlike Engine #2 shakes and hesitates ( might be time to tear that sucker down next) I will let you know how it runs after I get it in open water. Keep posting Rodbolt. You help a lot of people with your technical expertise. Thanks