Lost Power after changing outdrive

[slwootten73]

I recently replaced my Alpha 1 Gen 2 outdrive with a SE116 drive and have lost a ton of power to the water. My boat is a 1992 Bayliner 3.0l 4 cylinder with a gera ratio of 1:98. The new drive is also a 1:98 gear ratio but the boat will now only get to 3600 rmp while in the water with only 3 people onboard. Before replacing the drive I had no problem with power. This past week I took 7 people out on the lake and it would only turn 3000 rpm at full speed. When engine is in nuetral there is no issue with power as I can get to well over 5000 rpm. Is this a prop issues getting the power to the water from the drive or something else. Any help would be greatly appreciated. Shawn

 

[Bondo]

Re: Lost Power after changing outdrive

The new drive is also a 1:98 gear ratio but

Ayuh,... Welcome Aboard...

Are you Absolutely Sure of that,..??

 

[slwootten73]

Re: Lost Power after changing outdrive

This is what I was told when I bought the drive.

 

[Bondo]

Re: Lost Power after changing outdrive

This is what I was told when I bought the drive.

Ayuh,... Is it the Same prop,..??
Or atleast the same Pitch prop,..??

 

[slwootten73]

Re: Lost Power after changing outdrive

It also has a Michigan wheel 14x19 prop on it item number 031025

 

[slwootten73]

Re: Lost Power after changing outdrive

yes same prop was put back on

 

[Bondo]

Re: Lost Power after changing outdrive

yes same prop was put back on

Ayuh,... Then I would be verifying it's the same ratio....
Or,...
There's more to yer story...

 

[slwootten73]

Re: Lost Power after changing outdrive

If it is not the same gear ratio, is there anything I can do to get more out of it? I'm afraid by the way things sound that its not the same gear ratio I was told.

 

[slwootten73]

Re: Lost Power after changing outdrive

Also, How do I know the gear ratio as it is not written on the case. Thanks

 

[Bondo]

Re: Lost Power after changing outdrive

Also, How do I know the gear ratio as it is not written on the case. Thanks

Ayuh,... Either observe the difference between the rotation of the input shaft, vs. propshaft, or pull the top cap, 'n count the gear teeth...

 

[slwootten73]

Re: Lost Power after changing outdrive

If it is not the same gear ratio, is there anything I can do to get more out of it? I'm afraid by the way things sound that its not the same gear ratio I was told

 

[Bondo]

Re: Lost Power after changing outdrive

If it is not the same gear ratio, is there anything I can do to get more out of it? I'm afraid by the way things sound that its not the same gear ratio I was told

Ayuh,... I'm thinkin' yer Right...

Sell that drive, 'n get the ratio ya Need...

 

[slwootten73]

Re: Lost Power after changing outdrive

I'm new to this whole thing so please bare with me.. What drive ratio do I need? or can a prop change help. Thanks

 

[Bondo]

Re: Lost Power after changing outdrive

Ayuh,... You need a 1.98:1, or 2:1....

I really doubt you'll find a prop with pitch small enough to make up the difference....

My waGuess is, it's a 1.50:1, which is for a V8...

 

[Don S]

Re: Lost Power after changing outdrive

This is what I was told when I bought the drive.

Who did you buy this drive from? Was this an ebay sale where the guy just said yes so he could get rid of the drive?

 

[wca_tim]

Re: Lost Power after changing outdrive

In the shorter term while looking for a drive, you can pick up a lower pitch prop depending on what the gear ratio you wound up with actually is. if it's 1.81 a 17", if it's 1.61 a 15", if a 1.47 you're kinda sol.... unless you can run across something like a 13" prop hat will fit your drive. based on your new wot and assuming your wot rpms were right before, you most likely have a 1.6 ratio, maaaybe a 1.8 on it now... check the number of teeth mentioned as above and then do what makes most sense for you in the short and long term. You need the higher gear ratio to get decent performance though... Hope this is helpful

 

[slwootten73]

Re: Lost Power after changing outdrive

Bought it off ebay and was told it was a 1:98 gear ratio.I just took the top off and it has 24 teath. on the gear that is under the bearing

 

[Don S]

Re: Lost Power after changing outdrive

Need to know the tooth count on both the drive gear and the driven gear. They both have bearings.

 

[slwootten73]

Re: Lost Power after changing outdrive

24 driven gear 20 drive gear teeth

 

[HT32BSX115]

Re: Lost Power after changing outdrive

24 driven gear 20 drive gear teeth

24/20=1.20 You may have counted wrong. I don't think Merc made a 1.20:1 drive? (maybe it's a 1.36:1)


Another way to determine ratio is to remove the spark plugs(to make it easy to turn) and turn the engine 10 revolutions......have someone count prop turns....... If the prop turns 5, you have a 2:1 drive,

If the prop only turns a little over 6 1/2 turns you have a 1.5:1 (or so) drive

You can easily see 5 prop turns to 10 engine turns.

If you do not have a 2:1 drive, you need to get one. Your boat will never run right with a "high" drive" the 3.0L engine just does not produce the torque required......