Yamaha 15 mounted too high

[Hoppi84]

Was just out today with my 2020 yamaha 15 for the break in period... I got the first two hours done and running into what feels like surging when I throttle up quickly. It wasn't everytime and didnt notice it till the beginning of third hour... would having it mounted too high cause it or a carb issue... when I got the motor back in September it sat for a month and a half and was kinda of a pain to start why I said possible card issue... I have it mounted with cav plate at bottom of my jon... I'll get pictures of how high it is.. thanks in advance

 

[Hoppi84]

 

[JimS123]

What does "got it back" mean. "Break in period" indicates a brand new motor. "Pain to start" is confusing. You need to provide more data. "surging" doesn't compute

 

[Hoppi84]

I bought the motor back in September and the dealer fired it up and I took it home... it sat close to two months and finally had boat ready so when I tried firing it up it took a while before it started... I had to give more throttle before it started. Not sure I'd call it a surge but maybe the prop would take a sec to bite maybe. I did the hour 2000 and under and all was good and the get up on plane went good but I started the next 8 and that's when I noticed the hiccups before it took off throttling up quick. The gas was sitting since november-ish treated with stabil tho too.

 

[JimS123]

I'm totally cornfused.

Why did it need to be taken back? Two months setting is insignificant. Giving it more throttle to start it up is usually normal. what in tar-nation is hour 2000 and under, and even more than that what could possibly mean the next 8? November gas should be just fine.

Stop, take a breather, and try harder to describe in logical sentences what you are talking about.

 

[Hoppi84]

The motor was never taken back. I purchased it new back in September I haven't taken it out til today. I did the first hour of upto 2000 rpms and second hour of break in where you get boat on plane and back off throttle while still on plane. It wasnt til the third hour when I noticed the hiccups before it would bite and go. Trimmed all the way down kept it from every time but still did it occasionally. It's on my 1436 with a deck and my batteries up front and hopped up on plane quick.

 

[JimS123]

Hiccups and bite and go, and yet hop on plane quick are 2 different scenarios.

Take it back to the dealer, splain it all to him, and let him make the appropriate mods under warranty.

 

[99yam40]

I agree, a new motor and it is not running properly needs to be taken back to the dealer

 

[Hoppi84]

I planned on it but didnt want to make the hour and half trip if it was from being mounted too high. During the second hour easing into plane it didnt do it... it wasnt til the third hour when i noticed it. But I was giving more throttle. It was like the bumps when your lower goes but it would eventually take off. I never took to wot cause I felt something wasnt right with it but I wasnt thinking I had it to high

 

[Sea Rider]

Sitting a motor as pictured doesn't say much when in a dry motor installation once combo runs on water it's a much different scenario. What need to know is if it's a motor issue or a prop ventilating issue due to motor sitting too high on transom.

If motor runs OK, with motor trimed to 90 deg and once on plane running on flat calm water cond check at which lower leg is the hardened water flow is passing by. For that will need to pull your head side of motor and visually check that out.

Is the motor sitting right now flat on transom ? Those Yams having tall gap distance in between both plates as seen in previous posted pic doesn't like to be run sitting high on transom , that's with the water flow passing around the AV plate area.



This is a spot on Yam motor/transom height installation, water flow pasing right under the small upper plate where the prop achieves its best thrust powering just about anything that floats and in which you can sit in...

Happy Boating​

 

[Hoppi84]

I peaked at on plane and my top plate was definitely out of water unlike your picture. It was flowing off both sides and cascading off the bottom like a fountain. And that picture was all the trimmed up I believe. I tried all trim settings and there's was really no difference in bow lift and the steering didnt really seem to change either. I'm probably gonna drop it down to the top hole and see if it helps before I take it to the dealer an hour and a half away. It's only when I throttled up quickly that its noticeable but it just a sec like my prop lost bite before it grips and takes off.

 

[Hoppi84]

Ended up dropping it to the top hole. With the bottom hole the top of bracket was 1 7/8" from top of transom. Gonna run it again this weekend before taking it down to the dealer. Thanks and appreciate the responses

 

[Sea Rider]

Ended up dropping it to the top hole. With the bottom hole the top of bracket was 1 7/8" from top of transom. Gonna run it again this weekend before taking it down to the dealer. Thanks and appreciate the responses

Playing with different manual trim hole settings won't dial any improvement,



when the combo runs on plane the motor needs to work trimed at 90 deg on transom along a correct deck load distribution for a nice water performance. But if the motor is powering way high on transom will cancel any trim setting...

Happy Boating​

 

[Hoppi84]

Ya I understand that but I had it bolted to transom with the bottom holes so i dropped it to the top holes which its sitting 1 1/8" above the top of transom now.

 

[Sea Rider]

Ya I understand that but I had it bolted to transom with the bottom holes so i dropped it to the top holes which its sitting 1 1/8" above the top of transom now.

Sitting the motor at that precise setting in a dry terra firme installation doen't mean a thing to me as you won't know once the combo is running at plane on water at which lower leg's plates is the water flow passing by which is key to know to achieve top prop thrust, that's with a healthy motor running strong. Report with a wot run if the water performance has been bettered or remains almost the same ? No one should bolt any clamp motor on transom before knowing the combo performs well as expected, once there bolt it.

Happy Boating​

 

[Hoppi84]

Had it out today and pretty sure my issues were from being up so high. I couldn't get it to do what it was doing the last time out. I got a video I'm gonna try and get a picture with it running wot and how the top plate was running. At wot I was at about 5880-5900 rpm at about 26 mph. Its possibly still a touch high but not sure enough to drill more holes. thanks again and I'll post a picture later. Also I'm looking at getting another prop too and with those numbers would I be ok to drop a pitch down to a 9 or should I stay with the 10??

 

[Sea Rider]

To clarify :
That's a clamp motor that was initially installed high on transom for the AV plate to face the boat's botton, right ? If so, why don't you sit the motor fully down on transom, clamp it tight and check how it performs with a new wot run as before. Do you know the min-max wot rpm range factory stated for said motor? If it's 5K to 6K you're already there as currently were loaded, a less pitch prop will definitedly over revv it bad, which is nada bueno!!

Happy Boating​

 

[Hoppi84]

I had planned today to un bolt it and sit it flush with the transom if the issue persisted but everything seemed good. I may give it a run anyway with it sitting flush before re sealing the bolt holes. The wot rpm range is 5-6k on the motor. I appreciate your response and I'll let ya know how it goes just securing with clamps. Here's the picture running at wot of the top plate .

 

[99yam40]

is this a 4 stroke or a 2 stroke 15?
seems not many post up the true motor's model # anymore so it is hard to tell

 

[Faztbullet]

A lil deep in my book, install a 1x1 wood block under bracket to raise it and retest.