Mariner High Speed Miss

[Mariner60_hp]

60hp 2cyl 1980 Mariner<br />After tunning and piddling with most things on the ingnition and carbs I now have a stable idle, good excelleration and am happy, however I do have a occasional high speed miss. the miss occurs at wot. If I back of the throtle just a tad the miss goes away. I took out the spark plugs that came in the motor and did a cross reference on plus and came up with these plugs plus the factory manual plugs here is what I have discovered so far. This was done before tuning the engine( first thing I did was change the plugs) <br />Factory plug: b8hs .025 to 035 (high speed miss)<br />Autolite plug 4092 .025 to 035 (high speed miss)<br />Champion plug L78 .025 to 035 (high speed miss)<br /><br />The NGK wasn't to bad, the Champion was better and the Autolite was terrible.<br /><br />Now on the front of the carb cover is a large foil sticker that says NGK B8hs-1.0 which is to be gapped at .040, which is what was in the motor when I purchased it. Do you think this could cure the high speed miss?

 

[Mariner60_hp]

Re: Mariner High Speed Miss

Anyone got any takes on this

 

[Mariner60_hp]

Re: Mariner High Speed Miss

Replaced plugs with NGK B8HS -1.0.<br />Still has high speed mis. Anyone out there that can offer some help with this PLEASE

 

[Trent]

Re: Mariner High Speed Miss

High Speed Miss: <br />Disconnect the rectifier and retest. If the miss is gone, the rectifier is usually at fault. If the miss still exists, check the DVA voltage (between the red wires on 4 cylinder, or red wires to engine ground on 3 &6 cylinder) of the stator at high speed. NOTICE: Use caution when doing this and do not exceed the rated voltage range of your meter. The readings should show a smooth climb in voltage. If there is a sudden or fast drop in voltage right before the miss becomes apparent, the stator is usually at fault. If there is no indication of the problem, it could be a small water leak in one or two cylinders.<br /><br />Hope this helps?

 

[sharkcat]

Re: Mariner High Speed Miss

I would check plug leads for corrosion at both ends and for resistance you may have a lead braeking down.Also check float levels & main jets.If the float level is too low it may be starving for fuel at WOT.A main jet that is too small will do the same thing.Have you tried pumping the fuel bulb when it is missing?If the miss goes away when you pump chances are it a fuel pump going west...Good luck

 

[Mariner60_hp]

Re: Mariner High Speed Miss

OK, I have pretty much eliminated fuel supply as everything seems to be working correctly coils check good. plugs are new, with correct gap, however I seem to still have the occasional miss. I want to change the plug wires but the appear to be built into the coil. Do these wires screw into the coil or how do I replace them with out buying the whole assembly Look under ignition<br /> http://www.dougrussell.com/partscat...=7,14,1,4,5,16,10,2,9,8,19,18,12,17,3,6,15,20 ,21,22,13,11

 

[St. Johns River Rat]

Re: Mariner High Speed Miss

Wires are built into the coil. You probably have to replace the entire coil. Now this is not a bad idea if the coils are old. Wires crap-out faster than the unit. <br />Also, I chased a suspected high speed miss for over a year. Yeah, lots of patience. Several well respected/knowledgeable mechanics helped me with it. Turned out to be the lower unit mimicing the high speed miss. Came out of gear only at high speed.<br />Fooled even the best mechanics except for one old boy from Alabama. He just shook his head and said "damnset thing, get me a beer".<br />So, not to open a can of worms, look at everything. Old gears don't mesh like they are supposed to. Good luck.