[kentrx1]

--------------------------------------------------------------------------------

just traded engines on my pontoon (20 ft w/ 2 lg toons) . Had a late 1980's mariner and upgraded to a rebuilt early to mid-90's mariner. It has the automix oil where my older one did not. Question concerns the "backwash" I now get splashing up thru the opening in front of the engine. From about 3/4 throttle up it keeps the engine splashed pretty good----esp the bottom half of the engine cover down. The dealer said he swapped props to one that would better suit my pontoon and it does seem to be running fine----goes about 20 mph. Only have about 3 hours on the engine now and the first two were spent breaking it in slowly-----1/2 throttle first hour then 3/4 throttle 2nd hour. Is this splashing due to slightly different engine design or prop? Do I have any concerns from this? Engine is mounted as low as it can go, but in bumpy water it still pops out sometimes now----so really don't think I can raise it any-----even if that might help. It is not a bigfoot lower unit----just standard. Thanks for any suggestions/comments. Sorry I do not know the year of the engine. I was told the lower unit was late 90"s and engine early to mid- 90's. One other question concerning the tranny. I notice a different sound on engaging it than I did on my older unit. A little more "whine" at low rpm that goes away in the mid to higher rpm range. Is this normal? Thanks a bunch!!


kentrx1
View Public Profile
Send a private message to kentrx1
Find all posts by kentrx1
Add kentrx1 to Your Buddy List

#2 May 28th, 2007, 02:38 PM
tashasdaddy
Fleet Admiral
Join Date: Nov 2005
Location: jax,fl
Posts: 9,977

Re: 60 HP mariner backwash on pontoon

--------------------------------------------------------------------------------

i'd say it is running to deep.
__________________
FLORIDA GATORS REPEAT


tashasdaddy
View Public Profile
Send a private message to tashasdaddy
Visit tashasdaddy's homepage!
Find all posts by tashasdaddy
Add tashasdaddy to Your Buddy List

#3 Yesterday, 10:54 PM
kentrx1
Cadet
Join Date: Jul 2005
Posts: 6

Re: 60 HP mariner backwash on pontoon

--------------------------------------------------------------------------------

I tried using your suggestion and raising the engine. It was at the low point, and there are 5 total adjustment holes. I raised it up 2 holes, and there was no change at all in the water backwash. I rode the boat about an hour, and was concerned as it sounded as thou it was going to cavitate at the least wave. I have lowered it back and wonder it there is any chance that the prop can cause this. The engine and prop have not been on the pontoon before, but I did have a similar mariner i traded in that was the same hp and only about 2-3 years older. the water gurgles up thru the space where the engine pivots-----and this engine creates a much larger "v" spray than the old one did. It does push the boat great----and seems to wind up fine. The prop is a 13-11.5 I think.......best i can remember from looking at the numbers. Not sure what was on my old engine as it is gone! I wonder if there is any kind of "shield" that can block the water from shooting up thru the opening. Thanks for any suggestions!


kentrx1
View Public Profile
Send a private message to kentrx1
Find all posts by kentrx1
Add kentrx1 to Your Buddy List

#4 Today, 06:55 AM
tashasdaddy
Fleet Admiral
Join Date: Nov 2005
Location: jax,fl
Posts: 9,977

Re: 60 HP mariner backwash on pontoon

--------------------------------------------------------------------------------

post this in the boat topics, and questions forum. there are more Toon people there.
__________________
FLORIDA GATORS REPEAT


tashasdaddy
View Public Profile
Send a private message to tashasdaddy
Visit tashasdaddy's homepage!
Find all posts by tashasdaddy
Add tashasdaddy to Your Buddy List

#5 Today, 01:06 PM
j_martin
Petty Officer 2nd Class
Join Date: Sep 2006
Location: Isanti, MN
Posts: 181

Re: 60 HP mariner backwash on pontoon

--------------------------------------------------------------------------------

Did you change mid lengths to a shorter one?


j_martin
View Public Profile
Send a private message to j_martin
Find all posts by j_martin
Add j_martin to Your Buddy List

#6 Today, 02:32 PM
kentrx1
Cadet
Join Date: Jul 2005
Posts: 6

Re: 60 HP mariner backwash on pontoon

--------------------------------------------------------------------------------

I honestly do not know. A boat dealer rebuilt the engine and swapped it out for me----including the lower unit. Visually it appears to be about the same length. Is there a recommended length? Looking at the design of the lower unit, it appears that it "scoops" water up and shoots it up. Is there any kind of shield that would change this flow of water? I compared the depth of my prop to another pontoon and it was very similar----although a different brand of pontoon as well as engine----so it may not have any relevance. Thanks for your help.

[kentrx1]

talked to dealer today and he suggested i try bolting an extension to the hull in front of the motor. Anyone think this will have an effect?

[rickdb1boat]

You may want to extend the splash fins on the engine pod farther out and back with a somewhat down turn to deflect the spray away. Not sure what the dealer means by "bolting an extension to the hull"....