Back from the lake, have a few questions.

[TAC_Double]

Hello all....


Just got back from the lake after installing the 1975 85hp on the pontoon. Noticed a few things that were a little off and I am hoping you all have the answers.

All in all the engine ran well, very pleased with it on the pontoon.

I noticed that the boat does not plain out like it did before. Do I need to adjust the till lock pin to a differnet set of holes?

WOT RPM was at 3800. The prop that is on it is a 4 blade and I don't know the specs. I do have a 3 blade that I am going to try on it. I am correct in thinking that WOT should be between 5000 - 5500?

I also noticed that I could hear a chatter/grind when shifting from neutral to forward or reverse... seems worse going to forward. So I am pretty sure i moved some adjustment when I put in the water pump. Is there an easy fix?

Also notice the boat pulls to the right a bit... do i need to move the trim tab a bit to the right?


Thanks for any help or advise you can offer!

 

[hoeser]

Re: Back from the lake, have a few questions.

Firstly, if your WOT is 3800 you are either way over propped or the engine is not running correctly, possibly running on 3 of 4. WOT should be ~ 5500rpm.

Secondly, if your idle is too high you will get a shudder, chirp or grind going into gear... you want a ~700rpm idle in forward... if thats not the case, I'm not sure what the issue is as I don't have a lot of lower unit experience. I would assume clutch dogs though. You might want to check the lower unit oil for metal chips.

Thirdly, trim tab should be rotated clockwise to correct for a pull to the right. Make minor corrections, you will notice the impact is substantial.

 

[TAC_Double]

Re: Back from the lake, have a few questions.

More than likley the prop is incorrect. The motor cam off an old tri hull bass boat. I have access to a few other props, going to do some tests. And i can always take it to the shop and have them prop it correctly.

I did not pay attention to what the RPM was at idle in forward. I'll take a look this weekend. I am affraid that I moved the backet at the top of the shiftrod when I changed the water pump. It was not doing this before I did the pump. I fully tested it, before i bought it. Also, the gear fluid that came out was old, but had no water or shavings in it.

 

[ezeke]

Re: Back from the lake, have a few questions.

I think that you will want to move the rear of the trim tab to the right if the boat pulls to the right.

 

[TAC_Double]

Re: Back from the lake, have a few questions.

Thats what I was thinking. I will give it a small adjustment.

Does anyone know if this prop selector is accurate?

http://www.turningpointpropellers.com/default.php

 

[ezeke]

Re: Back from the lake, have a few questions.

I bought on of those for my 1976 115HP - used it once and it went on the shelf.

You should understand that selecting the propeller is the last step in the process of setting up the motor. When you do get there, run it by the people on the propeller forum.

They will want to know the legth and weight of your boat and what kind of load you will be carrying.

Regardless of the forum, picures of the setup help a lot. Try to get the A/V plate level with the boat to start, then adjust from there. If you can't get the pontoons to plane, you will not be able to tell what the WOT RPM is, so the rest of the exercise is futile.