Old Merc. 3.0L not 140hp?

[achris]

Re: Old Merc. 3.0L not 140hp?

does somebody know why the 3.0 GS was rated at 150 hp and the newer 3.0GL only 135?

If you had read all the posts in this thread (before posting yourself) you'd know the answer to that question. It was the reason for the thread in the first place.

 

[aerobat]

Re: Old Merc. 3.0L not 140hp?

If you had read all the posts in this thread (before posting yourself) you'd know the answer to that question. It was the reason for the thread in the first place.

well, i had read the posts, but both models ( GS and GL) were produced far beyond the crakshaft / prop rating discussion and should be rated the same way. so other carbs on these models ? maybe you can clarify.

 

[achris]

Re: Old Merc. 3.0L not 140hp?

well, i had read the posts, but both models ( GS and GL) were produced far beyond the crakshaft / prop rating discussion and should be rated the same way. so other carbs on these models ? maybe you can clarify.

Are both Volvo badged, so the Volvo forums would be the best place to ask the question. But the fact remains that Hp ratings have been all over the place, regardless of manufacturer or brand. Some are crank ratings, some are prop ratings, and some are numbers dreamed up by marketing divisions.

 

[Bondo]

Re: Old Merc. 3.0L not 140hp?

Are both Volvo badged, so the Volvo forums would be the best place to ask the question. But the fact remains that Hp ratings have been all over the place, regardless of manufacturer or brand. Some are crank ratings, some are prop ratings, and some are numbers dreamed up by marketing divisions.

Ayuh,.... Agreed,.... I'd say That, covers 99% of the "Hp Ratings"....

 

[bill 22]

Re: Old Merc. 3.0L not 140hp?

It would be good if boat manufactures had independent shops test and rate the hp of each engine. I know the marketing people would not like that!!

Thank you everyone for the input,

 

[achris]

Re: Old Merc. 3.0L not 140hp?

It would be good if boat manufactures had independent shops test and rate the hp of each engine. I know the marketing people would not like that!!

Thank you everyone for the input,

There is also a small issue with that too.. Small variations in component tolerances will make a difference in each engines' output. You may also have heard of 'blueprinting' (http://en.wikipedia.org/wiki/Engine_tuning#Blueprinting). That when an engine is built to the exact specifications and fully balanced, to produce the best possible engine to make the highest possible power output. The engine you fit to your boat (off the GM production line) is nowhere near the same as a blueprinted engine... So, if an 'independent' dynometer test was done as part of the process, the manufacturer would have an engine specially built up for that test... thus negating the whole purpose of the testing....

 

[bill 22]

Re: Old Merc. 3.0L not 140hp?

There is also a small issue with that too.. Small variations in component tolerances will make a difference in each engines' output. You may also have heard of 'blueprinting' (http://en.wikipedia.org/wiki/Engine_tuning#Blueprinting). That when an engine is built to the exact specifications and fully balanced, to produce the best possible engine to make the highest possible power output. The engine you fit to your boat (off the GM production line) is nowhere near the same as a blueprinted engine... So, if an 'independent' dynometer test was done as part of the process, the manufacturer would have an engine specially built up for that test... thus negating the whole purpose of the testing....

achris, very good point. I did not think about that.

 

[Tail_Gunner]

Re: Old Merc. 3.0L not 140hp?

Geez guys a lot of fuss of a 30yr old 4cyl. Heres a thought...the 3.0..2.5 are rev limited by the cam design that is the point where reving any higher will not acheive any gain..the cam profiles restrict any intake gain. With that in mind the valve train is built around that...Ever see light weight high compression springs and a high lift overhead cam in a 3.0 probalby not the engineering staff new better...Now lets marketing get involved thats another story, in the end who cares. Whether its 4400-4600-4800 its a old pushrod GM and out of wind

 

[achris]

Re: Old Merc. 3.0L not 140hp?

Geez guys a lot of fuss of a 30yr old 4cyl. Heres a thought...the 3.0..2.5 are rev limited by the cam design that is the point where reving any higher will not acheive any gain..the cam profiles restrict any intake gain. With that in mind the valve train is built around that...Ever see light weight high compression springs and a high lift overhead cam in a 3.0 probalby not the engineering staff new better...Now lets marketing get involved thats another story, in the end who cares. Whether its 4400-4600-4800 its a old pushrod GM and out of wind

Hey TG... Don't get the knickers in a twist... We're having a philosophical discussion here... Nobody died... Lighten up man...

All that you say is right, no argument... But a lot of people (me included) like to know the ins and outs of a pigs' bum... and having that info helps us be better people... (in our minds )

Chris......

 

[fishrdan]

Re: Old Merc. 3.0L not 140hp?

in the end who cares. Whether its 4400-4600-4800 its a old pushrod GM and out of wind

Well, that's kind of the point to some of these replies, to make sure the engine can turn those RPM's.... But yeah, it's only an ol' 3.0/181/140HP (or was that 120HP, No 130HP,,,, wait, I stand Corrected 135HP... LOL) and with not much sittin' in the bilge, you have to make the most of what you got.

 

[LilRedNeckGirl]

Re: Old Merc. 3.0L not 140hp?

just horse sence, 130, 140 whatever, its a small 4 cyl, and designed as such, a economical power plant for small craft. it was marketed by paper pushing sales men, hell bent on getting a one up on the compatition and closeing the deal. It could be made by Gm or Mercury Marine, but still its basicaly the same. both are covered in most repair manuals with only minor difference.
the truth in the matter,
its a reliable engine, that has remained basicaly the same for litteraly decades. It delivers both dependable and economical service, with only basic maintainace. its application is from runabouts to ski boat, from single to even twin units on larger craft. they offered during different years, one and two barrel carbs.
If you have one, be happy with what it is, understanding it is not a 350 cid high preformance unit.
you can Tweak it at the prop end to suit your needs, change the oil regularly, and enjoy the simplicity of one of the longest production engines ever made, or you can stress over the 3.0 , 181, 130 135, 140, horse power GM / mercruiser / mercury 4 cyl Industrial designed { yes they are found a lot in tow moters / fork lifts } modern marvel of an engine.
i run twins in a 25 footer with an 8 foot beam. I wouldnt trade them for anything. they start every time, every issue we ever had was basic maintanace and a $20.00 fix. we run all weekend on very little fuel considering all factors. For their size, they get us down the river crisp and clean.
And, when I need to repower with a new engine, The engines are affordable, abundant, and easy to install. It just doesnt get any better then that.

 

[viper1]

Re: Old Merc. 3.0L not 140hp?

I was also told I have a 3.0l merc i/o But the horse power says 180 hp. This is on a 19' 93 Starcraft holiday.

 

[achris]

Re: Old Merc. 3.0L not 140hp?

I was also told I have a 3.0l merc i/o But the horse power says 180 hp. This is on a 19' 93 Starcraft holiday.

At 180hp it sounds more like a '470' (3.7l). Simplest way to tell is where the carb is. Same side as the exhaust elbow = 3.0l, opposite side to the exhaust elbow = 3.7l... Post a photo of it and we can tell you...

Chris............

 

[sweet addiction]

Re: Old Merc. 3.0L not 140hp?

Yes, pics please.

 

[fishrdan]

Re: Old Merc. 3.0L not 140hp?

Tweak it at the prop end to suit your needs, change the oil regularly, and enjoy the simplicity of one of the longest production engines ever made, or you can stress over the 3.0 , 181, 130 135, 140, horse power GM / mercruiser / mercury 4 cyl Industrial designed { yes they are found a lot in tow moters / fork lifts } modern marvel of an engine.

That's exactly what the OP want's to find out, and is "stressing" over.....

Part of his original post below.......

Recently in a thread about performance of an old Merc. 3.0L, 140hp. It was posted that the old 3.0L are not really 140 horse power (maybe 115-120hp). I guess MerCruiser over rated the horse power? At sometime they rated them at 130hp, now the new 3.0L is 135hp.

1. What did they change on the engine to get the horse power back up to 135hp?

2. Besides a complete and detailed tune up, is there anything I can do to increase the horse power of my 1985 3.0L?

We are just answering his questions (and getting side-tracked a bit here and there).

 

[achris]

Re: Old Merc. 3.0L not 140hp?

... (and getting side-tracked a bit here and there).

I enjoy a good side-tracking....

 

[sweet addiction]

Re: Old Merc. 3.0L not 140hp?

According to my 1993 Mercruiser owners manual....there is a 3.0L which is rated at 115hp at the prop shaft and then there is the 3.0LX which is rated at 135hp at the prop shaft. Both have the same bore,stoke and compression. The 3.0 has a WOT of 4200 - 4600 rpm. The 3.0LX has a WOT of 4400 - 4800 rpm. The displacement is 4.3 liters/181 c.i.

 

[Bondo]

Re: Old Merc. 3.0L not 140hp?

The 3.0LX has a WOT of 4400 - 4800 rpm. The displacement is 4.3 liters/181 c.i.

Ayuh,... Right,........

 

[sweet addiction]

Re: Old Merc. 3.0L not 140hp?

Ayuh,... Right,........

I know, just saying exactly what the book says. I know 4.3l = 262cu

 

[Bondo]

Re: Old Merc. 3.0L not 140hp?

I know, just saying exactly what the book says. I know 4.3l = 262cu

View attachment 132334

Ayuh,... Have ya ever heard of a "Misprint",..?? Which that Obviously is....