1993 Mariner Magnum 3, issues while in the water...???

[jinxd12]

I had my Mariner Magnum 3 running like a top in my driveway with the hose kit on it. Felt like it was ready for the water...and got it to the lake, but had nothing but issues.

1- Took a little bit to get started and idle was barely enough tonrun.

2- After adjusting idle up a little and leaving the dock, attempted to get my boat on plane...3/4 throttle and it didn't have much power, so I let of the throttle and the motor stumbled and died.

3- I got it to start after 10minutes by tilting the motor up barely in the water. I putted around the lake for about an hour, never turning it off and maybe 1/4 throttle the entire time.

4- Had to cross the lake quickly due to many boats coming out, Gaga her a big throttle push and it was less power than the 1st time, and then died as I pulled back on the throttle.

5-10 minutes later I limped it in to the dock, motor tilted up and idle adjusted way up.

I'm stumped because it started so easily for over a week, in my driveway. Boat is getting fuel/oil and it is peeing as it is supposed to.

Any opinions or ideas? I'm thinking stuck carb floats, or something along those lines?

 

[Dukedog]

check compression and fire on all cylinders... what screw are you turning to up tha idle?.. have you got an oem manual?.. if not send me an email addy and i'll send ya a pdf file.............

 

[GA_Boater]

Three things, the same three things we always say - Check compression, check for strong spark and rebuild the carbs, including adjust the needles.

Looking at your other thread, you have carb issues. But don't skip the compression and spark checks.

In the other thread - What do you mean "went through the carbs"?

 

[jinxd12]

Compression is good, spark is good. Could probably use new plugs though. Tried to get away from rebuilding carbs, but might have to now. I cleaned them out with the good carb cleaner.

Adjusted at the bolt with the nut, towards the bottom of the left side if the motor.

The thing is it runs perfect on a hose, and like crap in the water...that's what doesn't make sense. Except no load I suppose. And it at least made it back trimmed up on the lake, which to me says something with carbs...but I'm no professional!!

Fuel line and bulb are good, possible line is to small? I think it's 3/8 or 5/16 hose?

I have a fuel pump rebuild kit, didn't want to do it unless it was needed.
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[GA_Boater]

No exhaust back pressure on muffs, that why it runs better.

Mechanic in a can never fixed anything and spraying carb cleaner in a carb doesn't clean the parts that get clogged.

I hope the motor was still getting enough cooling water tilted up to run. Might want to invest in an impeller.

 

[jinxd12]

It was just trimmed up a little, made sure it was still peeing, impeller is brand new. I'll look into a carb rebuild kit,

 

[Dukedog]

Compression is good, spark is good. Could probably use new plugs though. Tried to get away from rebuilding carbs, but might have to now. I cleaned them out with the good carb cleaner.

Adjusted at the bolt with the nut, towards the bottom of the left side if the motor.

The thing is it runs perfect on a hose, and like crap in the water...that's what doesn't make sense. Except no load I suppose. And it at least made it back trimmed up on the lake, which to me says something with carbs...but I'm no professional!!

Fuel line and bulb are good, possible line is to small? I think it's 3/8 or 5/16 hose?

I have a fuel pump rebuild kit, didn't want to do it unless it was needed.
​​​​​​

this tells me ya guessin' at everything ya tryin' ta do...one more time, DO YOU HAVE A MANUAL?

 

[jinxd12]

I have a manual, didn't have it on the boat with me at the time, need to get it printed so I can leave it in the boat. I was kind of guessing while on the lake I'll admit that, but when in the garage I have my tablet with manual.

 

[Dukedog]

if you were turning that screw ta move tha idle speed you ain't readin' it!.. tha only screw ya turn ta change idle (up or down) is 10/32 on tha timing arm...

straight outta tha book!

IDLE SPEED ADJUSTMENT
1. With engine in water, connect fuel line to engine. Start engine and allow to warm up.
2. Place outboard in gear and monitor engine RPM. If RPM is above or below recommended RPM (see specifications), readjust primary pickup (a) screw to attain recommended engine speed. Retighten jam nut.

 

[jinxd12]

ill have to go at it again today, from the MANUAL,

Is it possible to get real life water if i put the motor in a large trash barrel and fill with water, and eliminate the hose connections?

 

[jinxd12]

I am going to have someone rebuild the carbs, i have been quoted about $650 does this seem like a fair price...it included the rebuild kit and syncing.

 

[racerone]

And what if that does not cure the problem ??-----Post your actual compression test numbers from a test today.----Not numbers from last year.----And does spark jump a gap of 3/8" or more on a spark testing device, yes or no ?

 

[jinxd12]

Then I will move on to next possible issue...multiple people have said carbs. So suppose I should start there. Yes I have good spark, checked with a snap-on spark checker. Compression is good, when tested everything was in 120s?