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7.5cc K&B outboard Tunnel Hull Help

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7.5cc K&B outboard Tunnel Hull Help

Old 05-29-2013, 07:00 AM
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woodworker2001
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Default 7.5cc K&B outboard Tunnel Hull Help

Alright ... So new to the site and well I would consider myself very new to the r/c boat world. I built a Dumas Hot Shot 7.5 cc tunnel hull about 15 years ago. I blew up the 7.5 cc outboard back about 12 years ago. Finally got the parts together to get it going. I have a number of questions with this and am open to any all all advice with this engine whether it relates to my questions or not.

1. What should be a post run ritual for the engine?

2. How many turns out should I start with the needle valve and then also how many should you never go below.

3. What percent nitro fuel should be run for best results. I don't race the boat but as with everything faster is better

4. I ran it today and had almost zero throttle response out of the engine. Now all I had at the time was very old fuel about 10 years old. I know I know I probably shouldn't of used it but I did. Do you think that is the reason for poor throttle response?

5. What glow plug should be run in the engine? I know it will depend on fuel but give me some advice....

Thanks,
Dan
Old 05-29-2013, 08:28 PM
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Ron Olson
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Default RE: 7.5cc K&B outboard Tunnel Hull Help

10 year-old fuel should have been tossed out 5 years ago.
I answered most of your questions on another site except for I think for the glow plug. When I had one I ran McCoy MC-9's in mine.
Old 05-30-2013, 11:32 AM
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woodworker2001
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Default RE: 7.5cc K&B outboard Tunnel Hull Help

Ron.
thanks for the reply. Could you provide me a link to the other site where you answered my other questions?

i have a few others.

I have settled on 15% nitro I think to hopefully go fast but not push the edges of blowing the engine to far.
I have a panther 230 prop right now. Not sure how well It is balanced or sharpened to be honest. I have had many recommendations on props from octura x440 x645 or panther 225... What does everyone think?

just trying to learn here any and all help welcome

thanks
dan

Old 05-30-2013, 03:04 PM
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Jerry Dunlap
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Default RE: 7.5cc K&B outboard Tunnel Hull Help


ORIGINAL: woodworker2001

Ron.
thanks for the reply. Could you provide me a link to the other site where you answered my other questions?

i have a few others.

I have settled on 15% nitro I think to hopefully go fast but not push the edges of blowing the engine to far.
I have a panther 230 prop right now. Not sure how well It is balanced or sharpened to be honest. I have had many recommendations on props from octura x440 x645 or panther 225... What does everyone think? A Prather 230 should work o.k. Unless you want to spend a lot of money on props, stick with the Prather 230.

just trying to learn here any and all help welcome

thanks
dan


Jerry Dunlap

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