1989-90 bayliner 2159 hardtop.

[kcassells]

I have noticed that when Micky doesn't like something it doesn't seem to stay around too long.
Whatsdatsmell….???
New moto says I!

 

[zool]

My SF weighs in around 6k lbs and with the twin 171's (167hp each), only topped out around 35+-mph....I still cant imagine that peanut you got in there pushing that sled.

 

[mickyryan]

well new prop same rpm as the 3 blade 15 pitch except maybe 200 rpm lower with the 4 blade turning point.
oddly enough i got home put it on muffs fired it up , was running really rough stalled and died and has refused to start after that. starting to suspect the distributor parts the pickup and the timing module , replaced coil just now and still no go but was getting spark as per timing light but it was base mode timing and i wasn't in base mode lol got dark who knows man wouldnt it be sweet if it was this and the boat with this prop worked out , i wonder if weak spark was causing hp problems , it never smelled rich and didn'tt idle bad at all even on water today we kicked along at 1500 for over a hour no problem... i will get to bottom of it

 

[mickyryan]

I have noticed that when Micky doesn't like something it doesn't seem to stay around too long.
Whatsdatsmell….???
New moto says I!

I have been known to change a engine i didn't care for over a new "bigger size" because of a exhaust leak
My old 64 galaxie had a tired 352 that ran great but sucked hp wise so i heard a exaust leak and yanked it and put a 429 cobra jet in its place
life lesson: never fire a big block up in a basement when the lady upstairs has a blown ornamental glass collection ......

 

[Scott Danforth]

My engine is a 1992 3.0L and they call it 115hp. To know what you have for sure, you have to call Mercruiser with the Model Number and ask them to look it up.

From what I've read they call the same 3.0L engine anything from 115 to 140 hp depending on what boat they put it in. They're all the same engine though, literally part for part. They did that for selling purposes. That's what I've read anyway. I called Mercruiser and asked. Mine is a 115 hp and it came out of a Thompson Calae.

the difference in the ratings are as follows:

140hp is Gross HP rated..... back when the engines were rated at the flywheel with no accessories, spark arrestor or exhaust. basically this is all she has on the dyno
130hp is NET HP rated......back when the engines were rated at the flywheel with accessories, spark arrestor and the exhaust. this is what is at the flywheel when the motor is in the boat
the 115hp is prop rated...... this is what is really pushing the boat.

 

[66Holiday924]

That sounds familiar. I think it's basically what I read too. Additionally I read something somewhere that said the reason the different boat manufacturers decided to advertise the different HP ratings was for the specific sale of their boat(s). It is a good engine though. It's the most common, cheapest, easy to find parts for, reliable engine out there from what I've read. It's a direct decedent of the Iron Duke, but it's not the most powerful thing. I think it'll push my 1550lb Holiday just fine. People say they usually get 32-42mph on my boat, with that engine.

 

[mickyryan]

3.0 is fantastic engine , i know i am asking alot out of it but so far even the prop guy is stumped on what would work best lol the best prop i have found so far is a 504 cup prop "old" no clue how long its been out there or if its been worked on but pushed boat at 20@4k im not trying to go super fast i just want the right prop so it works properly
so far i have even cut down a 15x16 pitch prop to 14 to see if that made a difference and it didint about 300 rpm same speed believe it or not,
i have tried a 16x12 pitch 3 blade a 15x15 4 blade 15x16 4 blade blade a few others but im stumped and not getting anywhere really lol what seems to be is
15 pitch is around
15x13 pitch around 4 k @20
16x12 pitch 4k around 17 mph
i had thought about trying a 14x14 just to see if that would be the happy medium but i dont even know that they make one and id probably lose rpm based on my previous findings
13 pitch seems to be where it wants to be rpm wise ,
then there is rake and blade profile to contend with lol and cup.

 

[Scott Danforth]

from what I've read. It's a direct decedent of the Iron Duke, but it's not the most powerful thing..

that is incorrect

the iron duke is the pontiac 151 (2.5 liter). and shares nothing but a few bolts with the 3.0. literally only about 6 bolts.

the 3.0 a direct decedent of the 1962 Chevy 2 153 cubic inch (2.5 liter) which is the 4-cylinder version of the 230 cubic inch 6-cylinder (from the 196/230/250/292 family). With a bore of 3.875 and a stroke of 3.25". the engine saw most of its use in the Kaiser Jeeps (postal jeeps)

the 3.0 was developed as a stroked and bored version of the 2.5 liter (bore of 4.0 and a stroke of 3.6 - the 4.0 bore is shared with the 350), originally for natural gas powered fork lifts, then trash pumps and gen-sets. it was then migrated to the marine market since the marine engines are part of GM powertrain's industrial engine division. The 3.0 is built entirely in the Mexico GM engine plant

 

[mickyryan]

Scott, you wouldn't believe how many times I have explained that lol now i can just cut and past your response to save me time, im not sure where the rumor started that the 3.0 was the iron duke but its a myth that has been propagated forever. no offence to you holiday
also no parts from the original 4 except maybe fuel pump oil pump and tin will work on a 3.0 the journals are bigger
the old 120 had interchangable parts if i recall but once it went to a 3.0 it was a totally different beast.

 

[mickyryan]

so tonite i did the last thing i hadn't done after talking to prop guys all day and stumped a good portion who cared enough to listen i counted my teeth on the gears .... 24/24.... i have counted them 3 times and about to do a 4th so that would mean someone changed these gears to a v8 ratio ? why would they do that, but also i know guy had a ton of work done on this and seemed almost everything was new on engine as well so i now wonder if it was just a error no one ever caught.

 

[zool]

so tonite i did the last thing i hadn't done after talking to prop guys all day and stumped a good portion who cared enough to listen i counted my teeth on the gears .... 24/24.... i have counted them 3 times and about to do a 4th so that would mean someone changed these gears to a v8 ratio ? why would they do that, but also i know guy had a ton of work done on this and seemed almost everything was new on engine as well so i now wonder if it was just a error no one ever caught.

So if true, thats good, then you just have to swap that non iron duke peanut for a merc 260

 

[mickyryan]

So if true, thats good, then you just have to swap that non iron duke peanut for a merc 260

see ... i love that line of thinking , going to count again for 5th time to be sure

 

[zool]

I think, unlike the VP aquamatics, the Merc gear ratios are handled in the upper drive units, which can be expensive...best bang for the buck is to change the engine to match...

Im not dogging the 3.0/alpha package....I have one in my sea ray..its reliable and boring

 

[mickyryan]

well i agree on that aspect but i would like to know if this is why it has been so hard to prop , no matter what i could never get 4400 to 48 hundred rpm and the lower in pitch i went slower the boat got just checked again its def. 24x24

 

[Scott Danforth]

Micky......you could always go big block..,.

 

[mickyryan]

Micky......you could always go big block..,.

you know you my brother from another mother right? i wish i dont think it would fit Scott with your vast experience would this be my cause of prop woes ? and this poor little engine not able to push the boat?
side note... off to take measurements

 

[zool]

I dont think id want to put anything bigger than a sbc on an alpha....especially on that heavy sled ....Merc did pair the 454 with alphas with poor results......unless you granny throttle.

I do agree that the low rpms are concerning..even with a tired peanut on a sled

 

[mickyryan]

yeah id wind up going bravo if i was going to put that much effort into a big block , the small blocks measurements leave me a inch on each side of engine.. ugh its really why i wanted to make this work funny thing, i have talked to a few others on face book with same boat same add ons and they tell me they do 25 to 29 on their boat with 3.0 so if i could get that at wot id figure id be planing at cruising speed with 3.0 but maybe wishful thinking , never was going for speed but id like to plane at cruising speed lol.

 

[zool]

yeah, I wish I had an answer for ya, and forget the 4.3 option, little performance upgrade and will still be the v width engine......

Theres always the outboard bracket option with twin 225 Verados!

 

[Scott Danforth]

with the wrong gear ratio, there is no way to get the right prop, however take a look at this chart, if your drive is a later drive, the 24/24 could be right. my suggestion is to turn the engine over 10 times and count the prop turns

another option could be a cummins 4BTA-M at 250hp vs the SBC [h=2]Mercruiser Alpha 1 (1984 – 1990 Models)[/h]

2.5 Liter	120	2.5/153	4	1.98	20-24	1984-1990
3 Liter	130	3.0/181	4	1.98	20-24	1984-1990
165	165	3.7/224	4	1.84	17-19	1984-1990
175	175	4.3/262	6	1.84	17-19	1984-1990
180, 190, 470	180	3.7/224	4	1.84	17-19	1984-1990
200	200	5.0/305	8	1.65	24-24	1984-1990
205	205	4.3/262	6	1.84	17-19	1984-1990
230	230	5.0/305	8	1.5	20-22	1984-1990
260	260	5.7/350	8	1.5	20-22	1984-1990
350 Magnum	270	5.7/350	8	1.5	20-22	1984-1990

Engine HP Liters/CID Cylinders Gear Ratio Tooth Count Year

[h=2]Mercruiser Alpha 1 Gen 2 (1991 & Newer)[/h]

3 Liter	130	3.0/181	4	2.0	24-24	1998-2005
3 Liter	130	3.0/181	4	1.94	20-24	1991-2005
4.3 Liter	175	4.3/262	6	1.81	17-19	1991-2005
5.0 Liter	230	5.0/305	8	1.61	24-24	1991-2005
5.7 Liter	260	5.7/350	8	1.47	20-22	1991-2005

Engine HP Liters/CID Cylinders Gear Ratio Tooth Count Year