Enricher Valve

[Huggyd]

any ideas here?
I have been working on my 25HP merc 2002 bigfoot 4s
Last year it was running, not so smooth, I only run Prim Grade Gas in it.
I tested the key switch, all seems good there. Now I am thinking its might be the Enricher Valve so I took it off and with a 12v dc variable power supply I took 12V right to it and nothing happened.....hmm... must be that, I ordered new and tested that, again nothing..... My understanding it that the Enricher Valve is part of / is the chock, push the key in to chock, push the key and the Enricher Valve lets in a little more fule. Thus apply 12v and something should happen..... correct??????
The reason for looking at this was. I found most or all of last year 80% ish part of the time, the boat would start fine and idle a little rough, when the motor got up to temp, trolling around was rough and would sometime die when put in neutral

Anyone point me in the right direction??

[Moser]

This isn't my exact area of expertise, but I think on that 4 stroke motor the valve is open in the normal position, when the engine is cold, and as the temp comes up it closes to bring the mixture back to normal. It does not pop in and out like the old choke solenoids did. I would recommend the factory service manual as a reference for servicing the system. I think you are on the right track, but may not be looking at the system exactly as it works. The voltage that controls the enrichener is like 5 or 7 v.

Try boatinfo.no to access a digital copy of your manual. It is a tricky site to navigate and not always up, but they have a copy of every Merc manual there for all to see. I have a digital copy of that manual here too, but I cant look at it now. I'll check back later today, or you can PM me. I don't work on them a lot, but do have one good customer with one, so I see it every year.

One thing I did see on those motors that caused a similar issue. When you drain the engine oil from the drainplug and then put back the 1.6 litres it calls for, the engine will be over filled with crankcase oil. It does not all drain through the plug. When it is too full it starts hard and doesn't want to idle

[Huggyd]

"One thing I did see on those motors that caused a similar issue. When you drain the engine oil from the drainplug and then put back the 1.6 litres it calls for, the engine will be over filled with crankcase oil. It does not all drain through the plug. When it is too full it starts hard and doesn't want to idle"

Thanks for the info Moser. The above info, if this was the case, wouldn't it show on the dip stick, being over full, I do keep any eye on the level over the season.

[Moser]

Yes it will show. The one I had here the guy just changed it and put the prescribed amount back in it and never pulled the dip stick out. I was chasing down the rough idle issue when I found the oil too full. When the primers are not working right the engine will stay in the rich, warm up mode and the excess fuel will get into the oil "making oil" as they call it. Both of these issues will give you an overfilled crankcase and the rough idle condition. Checking the dipstick regularly is the way to catch either issue early

[Captain Tony]

Another reason I love the Optimax and other 2 strokes.

Better torque out of the hole and easier on the maintenance.

They also have their issues but somewhat easier to the "do it yourself" service boater.

[Moser]

If I could repower with any motor I wanted it would be a direct injection 2 stroke, Opti, ETEC, Yammy, they are all very similar.

[Huggyd]

I always figured the 4stroke were more reliable??
Still having rough idle issues. Not sure what else to look at, I still keep any eye on the oil level and haven't seen any change.

[Moser]

I'm thinking you have some dirty idle circuits, I would start ot think about cleaning the carbs or having it done. That is not something for the uninitiated to tackle, I clean outboard carbs every day and I would not tackle my Merc (Yamaha) 4S 50 without having read the factory manual on that process first, and having my certified buddy on standby. They are like an old school multi cylinder motorcycle, and they have to be properly synchronized or they will not work. If I did mine, I would have to take it to hm to tune with his gauges once I got it close. Sadly this is something that can eat up time at a repair shop, and cost big $$. If you get it done don't be afraid to ask if they have a tech who knows the set up, I would not want them learning on my motor. This is one situation where you like to see an old guy with lots of grey hair, a Camel in his lips and not to bad of a hangover that day.

4 strokes have a very good reputation for reliablilty, which they have earned. I am saying that IMO a 2 stroke Direct Injection engine, which is vastly different from the old carbed engines of the 80's 90's or even up to 200?'s, is a better choice of power for a pontoon.