Yamaha 2stroke question

[boslaw]

I have a 1997 Yamaha 200 on my 1997 Grady 208. The motor runs fine, but after running for a while, if I shut the motor off (fishing or hanging at the beach), it doesn't want to start again. The engine cranks but doesn't turn over. After half a dozen tries, eventually it will start but it idles really slowly. Once I get underway again, everything is fine.

I'm getting worried I'm gonna get stuck offshore while fishing and not be able to get home.

Any ideas what could be causing this problem?

Thanks

 

[PointedRose]

Have the carbs been cleaned recently at all? I’d also try new spark plugs if not replaced recently. some tips in this vid. Could also try a seafoam treatment

 

[seasick]

Since it starts OK when cold but not when hot, my first thought was choke but that depends on whether the motor is carbed or injected.
Next time as a test, when you have trouble starting the motor, turn off ignition and squeeze the primer bulb till firm (assuming it gets firm) and then try a restart.
Another piece of info that might help is what happens if you shut down for a longer while, like a30 minutes or more and then restart. I am trying to figure out if the issue is fuel or spark.

 

[steveditt]

Had a similar issue last season someone suggested a gasoline engineer that I had filled my boat with a winter blend fuel end of the season and it was boiling out when hot , I thought this was crazy until after my first fill up with again summer fuel It never had the issue again .

 

[boslaw]

Thanks for the replies. The engine is winterized and serviced every year by a Yamaha/Grady dealership. New plugs, etc.

I was having the same issue all of last season so I don't think it's a winter fuel blend issue.

I'll check the primer next time I go out to see if it's hard. If it's not, does that indicate an air leak somewhere?

I'm a complete noob when it comes to engine troubleshooting and repair.

 

[DennisG01]

As asked above... carb'd or F.I.?

 

[boslaw]

Sorry - carb'd 2 stroke Yamaha 200 Saltwater Series from 1997. I use Yamaha ring free with every fuel fill. Grady dealership told me carbs were fine, compression is good, new plugs, etc.

 

[seasick]

If you run it and stop for a short time, like 30 seconds, does it it start right up? If it sits for an hour, does it start right up?
If it has issues starting after sitting for say 30 minutes and an hour, or more, I would lean towards fuel starvation issue in which case squeezing the primer bulk will help ( but there still is a problem)

If it doesn't start after brief stops ( say 15 minute) but does after sitting longer like an hour, I would lean more towards a choke issue or an electrical problem .

It could be percolation (boiling of the gas) too. In that case, the motor will start after a brief stop ( 30 seconds or so) and after a cooling off period ( 30 minutes or more ) but not in between since the heat of the motor can cause the gas to boil.

Try the primer bulb first but before trying, make sure that if you squeeze that bulb you fell it get firm.

 

[boslaw]

Thanks very much. The motor usually starts after brief stops but not long stops (>30 min). I'll pump the primer bulb next time to see if that helps the situation. It's always embarrassing when you're at the beach with the kids and you have to spend 10 min trying to start your wheezing motor with your fingers crossed

 

[seasick]

At the beach do you raise the motors?

 

[boslaw]

Yes, but when I'm offshore fishing I don't raise the motor. I have the same problem in both situations.

 

[seasick]

OK, that helps me eliminate one cause, carburetor drain off when the bowls are tilted.
This one has me a bit stumped. Let's see what happens when the bulb is used.

 

[DennisG01]

Just kinda thinking outloud here - I'm only the fringe of my "carb" knowledge here, so maybe someone else can help clarify...

It sounds like fuel is draining out of the bowl. But I think in order for that to happen, the low pressure pumps on the side of the crankcase would have to be allowing fuel to seep past. IF this is the issue, then replacement gaskets (although it's not much more to just replace the whole thing) should fix the issue. I'll say this, though, if you don't know when they have been replaced last, just go ahead and do it anyways - they're considered a maintenance item.

 

[glacierbaze]

Not usually the gaskets that go bad in an LP fuel pump, but the diaphragm itself. With hoses still connected, loosen the mounting screws a few turns, until you can wiggle the pump, and give a few squeezes on the bulb. If gas runs out, the diaphragm is leaking.

 

[PointedRose]

I was thinking maybe the floater wasnt freely floating in the bowl in the carbs... might have gunked a little to make it a little sticky instead of moving freely.

 

[DennisG01]

Not usually the gaskets that go bad in an LP fuel pump, but the diaphragm itself. With hoses still connected, loosen the mounting screws a few turns, until you can wiggle the pump, and give a few squeezes on the bulb. If gas runs out, the diaphragm is leaking.

Yes, diaphragm... I was trying to think of the correct word as I was typing and that was the best I could come up with!

 

[seasick]

The strange fact is that the engine starts fine when either cold or sitting after a run. Bad LP pumps doesn't explain that. Carb seepage might but they would have the draining when resting (and the motor would be hard to start cold)

If after sitting and sitting for a while, the motor starts right up, it isn't a fuel issue in my opinion with the possible exception of vapor lock. I am thinking the problem is heat related. I am not sure if the fuel is cooled by water or if the ECI is also water cooled. If so, a partial blockage of the cooling system might explain a vapor lock condition.

 

[boslaw]

My mechanic guessed that maybe the fuel pumps need to be replaced (although this was based solely on the same info I provided in this thread). That seems like an easy enough job for me based on a youtube vid, but I don't want to waste a bunch of time & $$ if that's not the issue. I've learned from experience that even easy jobs often take longer than they should if it's the first time I'm doing them, and something usually goes wrong (drop a screw, buy the wrong part, etc). Boat is at a slip & I don't want to lose any time in our short MA season.

 

[seasick]

It looks like the CDI ( aka ECU) is not water cooled, nor is the fuel.
Can you verify the motor model. L200.... maybe or S200....

 

[boslaw]

Saltwater Series 2.
He did say that if the fuel pumps are the problem, then priming the bulb before a restart would make the problem worse.