Mariner 150 - High altitude, changed jets, no go!!!

[DocBob]

Re: Mariner 150 - High altitude, changed jets, no go!!!

I do know the thread size is the same...in fact, to order the 6 new idle jets, and the 6 new main jets all in .060 size, they were the same exact part number form Merc. (Part #1395-6487 listed as an idle jet, they don't even list a main jet in .060)<br /><br />And no way I'm getting up on plane. It dies at idle slowly, and dies instantly if I try to throttle up. I can idle and throttle up just fine in neutral, but nothing once in gear.<br /><br />No I didn't try it out before I made the changes...in fact, I should really check a few more things as well. I replaced the fuel filter and primer bulb...that would be my luck, there would be an air leak giving me the unburned fuel smell, and killing the engine...but if that were the case, would I still be able to throttle up in neutral?

 

[LubeDude]

Re: Mariner 150 - High altitude, changed jets, no go!!!

Can you pump the ball hard and it stays hard?<br /><br />I would still change the Idle jets back to stock, Its free, just a bit of time. A piece of wire will help fish out the jets, Been there done that. Dont know about the raw fuel smell.<br /><br />Next time out, have your cowl open and the air inlet off at first to look around for a leak somewhere. Dont tun the engin WOT with the carb cover off, Dont really know why, just heard not to.

 

[garyj]

Re: Mariner 150 - High altitude, changed jets, no go!!!

DrBob,<br /> Usually, if it is running lean at idle, it will "cough" or "sneeze" occasionally and usually die when you try and throttle up aggressively. If it is too rich, it will usually idle a little rough and miss as you throttle up until the main jets take over and then smooth out. I'm with LubeDude, go back to stock and then work the idle jets first. <br /><br />I'm really thinking there is another problem. The change in the idle jet size is minimal. I would think you should still be able to bring it to a plane (using the stock jets) by slowly advancing the throttle.<br /><br />Just for kicks, I would check the spark on all cylinders and be sure spark plugs are good.<br /><br />SC

 

[LubeDude]

Re: Mariner 150 - High altitude, changed jets, no go!!!

Originally posted by Southern Catfisher:<br /> <br />I'm really thinking there is another problem. The change in the idle jet size is minimal. I would think you should still be able to bring it to a plane (using the stock jets) by slowly advancing the throttle.<br /><br />SC

Also try pushing in on the choke button while trying to get on plane, (have someone hold the wheel), or push the choke in just a second before you accelerate. If this works, you are lean. if it kills the engine you are rich.

 

[DocBob]

Re: Mariner 150 - High altitude, changed jets, no go!!!

OK, it sounds like I have a few things to try. I'll check those plugs...they were new last year, and I didn't run it all that much, but who knows, they could be fouled. That engine is getting older.<br /><br />My choke is on my ignition switch. It activates when I push in on the key while starting. I did notice that even after running for a bit, the engine wouldn't start without pushing in the choke so does that typically mean it is running too lean? I never did try choking it again after started though...good idea. <br /><br />I guess I'll let this rather verbose post die, and start again after checking the spark and choke options. Hopefully it will turn out to be something simple like the spark plugs. <br /><br />Anything else I want to check while I'm at it?<br /><br />And thanks for all the help and ideas, this site is great!!!

 

[walleyehed]

Re: Mariner 150 - High altitude, changed jets, no go!!!

This engine has mechanical timing advance doesn't it guys??? I'm not sure of the set-up on the merc/mariner...<br />On the OMC's with mechanical timing, at 6000ft I would be 3-4 degs above max timing, maybe even 5 degrees.<br />After you get the jetting figured out (I don't feel that is your issue) check max timming as it is and report back..

 

[DocBob]

Re: Mariner 150 - High altitude, changed jets, no go!!!

Thanks Walleye...I'll do that.