WOT only when my motor is in the mood???

[DocBob]

My 150 Mariner idles fine, and even motors along at about 10 mph with no problem. <br />When I give it the throttle, it does one of two things. It either responds as expected, jumps on plane and the world is beautiful. I can even slow it down to avoid the monster wakes from the cruisers out on the bay, and then jump right back to WOT.<br />At other times when I give it gas, it thinks about it for a second and then decides to die. It starts right back up every time, then I give it the gas and it dies.<br />I can rev the engine eanytime in neutral (with no load of course) and it never dies.<br />But under a load, it has to be in the mood to go. If it was everytime I throttled up, I would think it might be the timing, or the carbs, but would these cause these symptoms?

 

[sharkcat]

Re: WOT only when my motor is in the mood???

sounds like the idle mixture is too lean.but to be on the safe side check the timing & do a link & synch.Then adjust the mixture screws with the engine running in gear in the water.Your manual will tell you how.You do have a manual dont you?Dont try to adjust the mixture screws running on muffs as there is no back pressure & setting you get will be too lean, the motor will then stall when you put it in gear in the water...hope this helps

 

[DocBob]

Re: WOT only when my motor is in the mood???

Thanks sharkcat, yes I do have a Clymer manual for the engine. Couldn't they pack a few more models & horsepowers in there...it's not quite confusing enough!!! <br />I'm no mechanic and would have never even thought of checking the idle mixture for this problem. I'll check those settings, and then give the idle mixture a check next time I'm out.

 

[sharkcat]

Re: WOT only when my motor is in the mood???

the manuals are a bit confusing,what I do is photocopy the relevant pages for the motor Im working on then refer to the copies.Keeps the manual clean & stops any confusion.You might need a beer or better yet two 1 to drink & the other to stop the copies blowing around

 

[The Marine Doctor]

Re: WOT only when my motor is in the mood???

If the idle screws do not help..its time to rebuild the carbs. Do your carbs have the idle circuit with the plate on top? If so it possible that its leaking air in.<br /><br />TMD

 

[DocBob]

Re: WOT only when my motor is in the mood???

OK sharkcat, I got the beers (I always keep a few extras around) and then checked the manual. It turns out my engine does not have idle mixture screws. The mixture is not adjustable because this engine uses "jets". OK, one beer down.<br />I pulled the jets and cleaned those, another beer down.<br />To answer The Marine Doctor, yes this motor has the plates in top of the carbs. Of course you can't get to them without pulling the carbs off the powerhead. I will have to get a set of replacement gaskets before I tackle this job. There are three two barrel carbs on this engine. Should I be worried, as a mechanically declined individual, about getting them synchronized when I put them back on, or should I just let someone who knows what they are doing rebuild them?<br />This engine had been left for a few years without starting, and overall is running surprisingly well in spite of the fact that I did all the work on it... <br />I'm sure the carbs were well gummed up from sitting that long. Is it possible they are cleaning themselves as I run the motor...it seems to run a little better each time I take it out. Or is a rebuild unavoidable?<br />Thanks again, y’all are very helpful…I’ve already save a considerable amount of money on the work I’ve done thus far. I had planned to get the boat to a mechanic at some point for the final tune up, but thought I'd keep going as long as I could without messing something up.

 

[sharkcat]

Re: WOT only when my motor is in the mood???

good to hear you are well oiled Does the engine run any better now you have cleaned the idle jets?A link & sync definitely wont hurt & dont forget the beer Are the jets the right size?Check the numbers with the manual.

 

[DocBob]

Re: WOT only when my motor is in the mood???

Is a link & synch difficult? The manual sounds a little confusing, but I've found most of the tasks are actually relatively easy when you actually get down to it. <br />According to the manual, the only time I should have to change the jet size is if i move to a higher altitude. I didn't notice a size on them. Is that stamped somwhere. I could pull one and check it. <br />And yes, It does seem to be running better, but not a complete fix yet. Like I was saying, the engine seems to run a little better each time I take it out. Will a gummed up carb clear itself over time if it's run, or should I just bite the bullet and tear them down?

 

[PeteMax402]

Re: WOT only when my motor is in the mood???

DrBob, <br /> I just spent the time rebuilding a 40hp Merc because the carbs were gummed up. Burnt the top piston because the lube is in the fuel. I would tear them down clean em out and then enjoy the boat not worring about whether today will be the last day you return to the dock with out a tow. I also know that these engines run better when they are leaned out a little. This means that there is not enough lube and you "Grenade the engine". Hope I changed your mind.

 

[DocBob]

Re: WOT only when my motor is in the mood???

Thanks for the info Pete. I knew I would have to get around to rebuilding the carbs at some point, but didn't think about it causing a problem with the lubrication. Than makes sense though...two cycle engines only get there lube through the fuel, and if the fuel isn't getting to the cylinder, the oil isn't either.

 

[Merc90HPnewbie]

Re: WOT only when my motor is in the mood???

Stupid question- what's a link & synch procedure? I don't see it in the Seloc manual.<br /><br />Thanks!

 

[sharkcat]

Re: WOT only when my motor is in the mood???

Newbie there is no such thing as a stupid question there are just stupid answers ...This is one of them Seriously Link & synch is: Set the ignition timing at idle & WOT,make sure throttles are all closed then set the clearance between the roller & the linkage as per specs.Open the mixture screws as per specs.Clean & reset or replace plugs.Then start engine allow it to warm up & adjust idle mixture with the engine in the water & in gear & youre done