Marlin 300 stock F225 motor height? Prop size?

[Wrightsfd]

Hi all, I've searched for this topic here but found nothing. I know the rule of thumb for this but figure I'd ask those of you with similar boats. My "new to me" 2003 Marlin 300 has the original Yamaha F225s (only 600 hours and freshwater all their life!) I have the boat out of the water and notice the motor mounts are all the way down. But I see the motor was mounted in the 3rd holes from the top at some point. P.O. says he knows nothing and it was that way when he bought it used in 2005. Props are 17" and it was a troller so I assume the motors were brought down to accommodate those conditions. Now, here is the question: What hole are your Yamaha F225s mounted? I think I should bring these motors back up to the 3rd hole which will put the AV plate just slightly above the bottom of the boat. But I think the 17" props may be out of the water, so do I now need to go to the stock size props? I think they were 14 1/2". Thanks for your input!

 

[Jrspawn]

Not sure where the factory position was. But with my f225’s, I have them mounted in the third hole(second highest mounting position). I run ofs4 15.25x17 props. I thought about switching to a 16 pitch version of the prop as my max rpm’s are on the lower side of the suggested range, but will probably just stick with the 17’s. I’m very happy with the performance!

 

[Ekea]

you need to determine where the water is relative to the anti ventilation plate when you are running on plane. if its below the water, you should raise the engine. it should be right on the surface of the water. as long as that is making contact with the water, you know your props will be under water.

go out with someone and have them drive while you (safely) find a way to look at the plate, or put a gopro on a stick

 

[Wrightsfd]

you need to determine where the water is relative to the anti ventilation plate when you are running on plane. if its below the water, you should raise the engine. it should be right on the surface of the water. as long as that is making contact with the water, you know your props will be under water.

go out with someone and have them drive while you (safely) find a way to look at the plate, or put a gopro on a stick

Thanks. I have the boat in storage now with access to a fork lift, I thought it might be easier to do it all now than running back and forth to and from the lake/storage which is at least an hour each way and I need to get WideLoad permits to go through town. But I know you’re right that I should check it. Right now my AV plate is about an inch or more below the bottom of the boat which seems quite low.

 

[Ekea]

Thanks. I have the boat in storage now with access to a fork lift, I thought it might be easier to do it all now than running back and forth to and from the lake/storage which is at least an hour each way and I need to get WideLoad permits to go through town. But I know you’re right that I should check it. Right now my AV plate is about an inch or more below the bottom of the boat which seems quite low.

so, to get started with it where it is, a general rule of thumb is that the plate should be one inch above the running surface for every one foot it is behind the transom. it sounds like you are definitely too low right now