mercruser 888 wont rev past 2000 when in gear in the water

[alldodge]

You should have 1.5 to 1 maybe. Motor turns 1.5 for every time the prop turns once

 

[mauro.]

so do you think this is my issue

 

[alldodge]

so do you think this is my issue

Maybe in part, but

Did boat ever run good with old motor at speed with 17P prop?
Meaning could reach WOT rpm and all

If answer is yes, then the problem is probably your new motor
If answer is no, then could very well be the drive

Now if it's neither yes or no, then we need more info

 

[mauro.]

I have never seen that boat in the water before I bought it. it was supposed to be rebuilt engine sterndrive and all but then the guy passed away and when his friend sold it to me 3 years later every thing was all rusty inside the engine so had to clean every thing out and when it finally ran it had that issue and I have been trying to figure it out ever since. another thing is that when i put the old three blade 17 pitch it will get on plane and run at around 2500 when trimmed out

 

[mauro.]

Ok so I checked again 1 engine rotation will give me a little more than 3/4 of a prop rotation so sorry about that false info before. The sprocket in the oil chamber that is right after the u joints of the leg has 18 teeth is that correct? I thought that it was supposed to have 20 or 22 not quite sure though

 

[mauro.]

checked compression again just to be sure and all were at 145 and 150 psi so not bad at all. Spark plugs are white at the gap setter so am I running lean you guys might be right that I have a fuel issue maybe too small jets wrong power valve? or I guess fuel pressure too low I will have to test that but I am pretty sure that it is not the case as it is one of those mechanical pumps with the sight glass that is supposed to show faulty pump. I don't know though if it will also show fuel if pump is not putting out enough pressure

 

[Scott Danforth]

What is base timing? What is all in? At what RPM?

Verify the ratio. It should be 1.5:1

 

[mauro.]

base timing 10 btdc 34 all in at around 2000 rpm ratio is either 1.32: or 1.29: so less than supposed to bee will that make a significant difference? thank you
Mauro

 

[alldodge]

base timing 10 btdc 34 all in at around 2000 rpm ratio is either 1.32: or 1.29: so less than supposed to bee will that make a significant difference? thank you
Mauro

Yes, like taking off with a manual transmission in high gear
Another thing that can cause issues is the hull, is it water logged (as in heavier then it should be)

 

[kenny nunez]

Many years ago I had a customer who pulled up a boat with a V6 OMC that had sunk during a hurricane. After repairing the engine along with everything else the boat would barely plane. Turned out below the deck was a solid mass of mud.

 

[ROY WILLIAMS]

base timing 10 btdc 34 all in at around 2000 rpm ratio is either 1.32: or 1.29: so less than supposed to bee will that make a significant difference? thank you
Mauro

THE gasoline 93 octane timing BTDC 10 ... the gasoline 90 octane 6 BTDC degrees timing ...
idle 650-850 rpm ..............
the engine MCM 888 oil zinc plus 6 oz. ENGINE OIL 30 WT 60F-85F .. ENGINE OIL 90F HIGHER 40 WT ...
1978 MERCRUISER 2 MANUAL BOOKS C-90-71707
20 FT/25 FEET BOAT WEIGHT 3K-4K PROP 15 3/4 - 17 INCH 1.32 ....

 

[Scott Danforth]

base timing 10 btdc 34 all in at around 2000 rpm ratio is either 1.32: or 1.29: so less than supposed to bee will that make a significant difference? thank you
Mauro

Those are big block ratios. You need a lot more motor to spin that ratio

 

[mauro.]

ok I will have to look for a 1.5 or 1.62 upper as it is the one that has the drive shaft driven at 16 teeth insteat of 24 and the drive shaft drive gear has 20 instead of 24 teeth which lead me to the wrong ratio of either 1.32 or 1.29 instead off 1.5. As for the boat being water logged is not possible I had the whole floor out and redone. Do any of you guys know where to find one of those upper legs used in the BC area? I will let you guts know how it will go.
Thanks for the help
Mauro

 

[Scott Danforth]

Could bolt a 671 on top the motor

 

[mauro.]

what is that a carb I know it is a weird question

 

[mauro.]

sorry wasn't clear what I wrote. What so you mean with a 671? is that a carb or something? Sorry if it is a dumb question but I am new to that terminology.
Thanks a lot
Mauro

 

[ROY WILLIAMS]

sorry wasn't clear what I wrote. What so you mean with a 671? is that a carb or something? Sorry if it is a dumb question but I am new to that terminology.
Thanks a lot
Mauro

CARB MODEL 2GV 7044185, 7044187, 17056197 / HOLLEY G317-1

 

[alldodge]

A 671 is a blower

 

[mauro.]

will that help? isn't it way more expensive than a set of gears?

 

[racerone]

The 671 blower was meant to be a " funny one " in my opinion