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[GreenMachine]

Hi, So I picked up a new to me used boat a couple weeks back, fired up when we went to look at it, once we got home we started it in the rain barrel, everything was good, finally got registration on the trailer today, so why not take it to chestermere for an hour to see how fast it goes,
Fired right up at the dock, untied the boat and off we went, was good at low to meduim throttle, but  soon after we went to full throttle it cut out. we started it back up, ran good at low rpms, and then died at full throttle,
we didnt have any luck starting it again, probably because my arm was tired, and I think the gas might have been bad,
we paddled over to a dock and one of the guys on the lake was nice enough to launch his boat and tow us back over to the launch with his 200 hp ski boat,

got the motor home, stuck it back into the rain barrel, with new gas and it fired right up, idles fine, runs fine in gear, but at full throttle it dies back down, and cuts out, I dont know to much about small engines, but I know enough to get by and know when something is wrong,

any ideas would be great!

Wayne

[Vinman]

Clogged fuel filter?

[GreenMachine]

Yeah thats something I thought, Because it only dies when its W O T, Im gonna pick up a shop manual hopefully tomorrow.

But definitely a fuel issue?

[hornblower]

I had this happen on a new to me boat. She seemed to work well on land but when she hit the water and opened up it would cut out and die.

I searched high and low for answers. I changed fuel line, filter and checked the carb. Could not figure out why it would run fine then die out when it was wide open.

Turns out there was two problems. One is the prop had a slight bend that was causing it to catch on bottom leg when full open, Thats an easy fix with a set of vice grips and some man handling. Second was that when it was full open the spark plug wires were shaking loose off the plugs. Another easy fix with the zip ties.

Maybe this will help. If you need some assistance I have a bit of knowledge of the outboards so just shoot me a pm.

Matt

[BUKI]

Maybe carb issues...?   Accelerator pump? Float out of adjustment, too little fuel in bowl??

[GreenMachine]

I looked into it a bit more today, it's an 85 merc 7.5hp,

There is no fuel filter, so I'm hoping it is just dirt in the carb, i will be cleaning that out, and will be adding a fuel filter, is there any kind I should or shouldnt get?
Changed out the spark plugs. All wires seem to be tight.
I managed to track down a shop manual today and will picking it up tomorrow.

[mike s]

fought the same problem on my 'ol 70hp Johnson, ended up being a bad condersor for the points, yours might have points still.

[LukeDuke]

Does it cut right out or bog down and die? If it cuts right out then i would suspect an ignition problem weather it be points, condenser wires or plugs, if it bogs then dies its definitely fuel supply or delivery.

[GreenMachine]

Bogs a little, I felt it start to die, I would throttle back, then it would die, all with in a few seconds

[GreenMachine]

So there is a fuel filter right on the carb, I talked to the previous owner and he gave me the papers saying the motor had been in the shop last year for a tune up, and the prop seal was replaced,

I know the motor came stock with a two blade prop, now has a 3 blade, With our old motor someone told me it was bad to switch one to the other? is this true and should I consider changing it back to the two blade that it came with?