695 Marlin questions

[grantiv]

I recently bought a 2017 marlin 695 with a Yamaha 175. I ran it the other day and WOT on a flat day it was doing about 32mph at about 4500 rpm I’m pretty sure it has the wrong propeller on it. Does anyone know what size and pitch the propeller should be or what theirs does just for reference Thanks !

[rene460]

Hi Grantiv, welcome to the forum, and congratulations on your purchase.

I am wondering why you think the propellor is wrong.  Have you checked the maximum specified rpm for your motors.  This is a sound indicator of whether your propellor is properly loading your engine.  So how does your observed 4500 rpm compare with the specified maximum?  This is the first step in understanding the problem.  Generally the guide is wot should be at max 10% over the maximum specified rpm, but a little less should not be a problem.

Someone with that engine might come in and advise what they have, but in the mean time, establishing the performance parameters will give a good indication of where you are up to.

It is also worth browsing the forum with a few search parameters as there have been a number of threads on the topic.  I am just not sure if your particular combination of engine and hull have been covered.

rene460

[grantiv]

Thanks for the feedback. From what I can find the rmps should be around 5500 to 6000. I also spoke with a Yamaha mechanic he said it should be around 5500. I plan Purchasing a stainless propeller for it just want to make sure it’s the right one. It may be right not sure just 4500 seems low to me

[rene460]

Hi Grantiv,

There should be some documentation for your engine which gives a rated rpm and a maximum rpm, however, assuming it is in the range of 5500, then 4500 rpm at wot does indicate that the propellor is overloading the engine.  But still worth finding the specifications so you know what you are aiming for, and for future monitoring any performance changes.

First thing is to check the propellor carefully for nicks and dings which disrupt the smooth flow of water over the propellor.  It does not take much at such high rpm to seriously increase the drag of the blades, remember, they are like wings moving through water, and this increase in drag requires more torque to drive so prevents the engine reaching its intended maximum rpm.  If it has touched a rock somewhere, repair may be possible, though it is best carried out by an expert, as there is a risk of upsetting the propellor balance if it is not well done.

I can’t advise you what size propellor would be more suitable.  Usually there is not much range of diameter available for an outboard.  It may be possible to go a bit smaller diameter, but mostly, I would expect you will need a bit less pitch than your present propellor.  This will allow the engine to run the propellor faster and give more thrust, and hence higher boat speed.

I would suggest talking to your proposed propellor supplier.  I believe the specialist ones will help you arrive at the optimum size and possibly even offer a loan propellor for testing.  If you are planning to go for a stainless propellor, you want to have a supplier who will help you select the right size.  Their business success depends on their being experts, and I expect they will want to help you get it right.  And a stainless propellor is too expensive to risk getting it wrong.

Rene460

[lynnardm]

Aug 23, 2021 2:17:34 GMT grantiv said:

I recently bought a 2017 marlin 695 with a Yamaha 175. I ran it the other day and WOT on a flat day it was doing about 32mph at about 4500 rpm I’m pretty sure it has the wrong propeller on it. Does anyone know what size and pitch the propeller should be or what theirs does just for reference Thanks !

Grantiv ,

I had a 695 non sport with a Yamaha 200 prior to my 895. I don’t recall the propeller. This is not a direct comparison to your boat but should be a good reference. I could hit 40 mph and 6000 rpm. So I would expect your WOT speed to be in the mid to upper 30’s. Somethings not right. Propeller, engine trim, engine height, boat hull condition, engine condition??!!

Capt’n Lynn

[grantiv]

So I got in touch with Jeanneau and they sent me a chart with the correct propellers for each model and It was the wrong propeller! Bought the new one and works great now. Thanks for the help! I’m trying to post the charts incase anyone else is having issues does anyone know how to post a photo?

[rene460]

Hi Grantiv, glad you got it sorted.  It would be interesting to know what the previous propellor was, and what you have now.  The difference will tell you a little more about how propellor dimensions work with the engine.  What rpm and boat speed are you getting now?

To attach a picture, first make sure you have a copy in your photo folder.  To post it, it needs to be less than 1 Mb, but 300 - 500 kB is quite adequate in my experience.  

When you open the edit box to post a reply, there is an “add attachment” box on the top right hand side, just above the box where you type.

Some devices give you a size option when you attempt to post, so give it a try.  

Now you have a satisfactory prop, make a note of the wide open throttle rpm and boat speed for future reference.  Run at wot for a few minutes when you get suitable conditions, as any change will alert you to engine performance or propellor damage issues.  

rene460

[grantiv]

The original propeller on it was a 14 1/4 x 17 and the new one is 14 1/2 x 15. It made a huge difference, better hole shot and higher top speed . I took it out yesterday and now it does around 40mph at around 5500 RMP. It wasn’t very flat tho so I wasn’t able to trim it out perfectly to get the exact numbers. I don’t have the add attachment option for some reason I’ll try it on my desktop later

[rene460]

Wow!  That is a serious reduction in propellor size.  It shows how important it is to properly match the propellor to the engine in order to efficiently turn the maximum available engine power into thrust.  And the increased thrust is clearly shown by the extra speed you obtained.

Also, your engine will reward you by lasting longer when it is not being seriously overloaded. 

rene460

[goonerbertie]

hi Grantiv, I'm struggling with a similar issue on my 855 and have just created (yet another!) thread on prop size. I'd very interested in seeing your chart, or at least knowing how you got it from Jeanneau.

[grantiv]

Hey yea I have the chart it has your boat on it just can’t figure out how to upload it … what motors do you have I can just type it in if you’d like

[grantiv]

I emailed a guy named Gilles from Jeanneau his email is [e-mail] he sent me the charts took a week or so to get a response. If not you can leave your email or number I have no problem sending that way either