does this sound right? 43mph from a 50hp?

[flyinbryan]

in 1995 i purchased a new mercury 50hp outboard to put on my 1995 16ft astro bass boat (actually says 15'3" on the title). then something strange happened.

a few weeks later i found out that the 1995 engine i bought brand new, from a dealership, was actually a 1993 engine. (i found out because i noticed on the brochure i had gotten that it had a different cowling graphic than mine) i ended up calling the dealership, and they said they were sorry for the mistake, and asked if i would be happy if they threw in 5 cases of oil, and 3 extra years of full warranty. i said sure, sounds good, since i got a good price on it anyway.

shortly after, things started seeming strange. folks kept asking me "how fast will it run?" ,,,,,,,,,"oh, 42-43mph"

everyone said no, aint happening, but to this day, the little boat will indeed run 43mph.

a few years pass by (like ten) and its time to rebuild the carbs so i go buy the clymer service manual, and i have to use the 75hp section (3 wme carbs, and variable rate oil injection) according to the manual, everything i can do to the engine requirtes me to reference the 75hp sections of the book.

my motor says "50" in 3 places. the back of the cowl, and each upper cover of the motor leg.

is it possible it is not a 50? or have some of you heard of a 50 with 3 wme carbs, and variable rate oil injection?

 

[mercuryman25]

Re: does this sound right? 43mph from a 50hp?

could be a 75 hp powerhead.

 

[verado7]

Re: does this sound right? 43mph from a 50hp?

i get 40 - 43 mph on my 15'5 sangster flat bottom with just myself in it . and i have an 88 classic fifty ( 45hp) 4cyl. with a SS prop

 

[achris]

Re: does this sound right? 43mph from a 50hp?

Post up the serial number and we can check it for you. Also a photo of the engine would help.

Chris.......

 

[Faztbullet]

Re: does this sound right? 43mph from a 50hp?

have some of you heard of a 50 with 3 wme carbs, and variable rate oil injection?

Yep.. All the 40/50/60 (3 cylinders) from 1991 till about 2007 have the WME carbs and variable oiler...

 

[Expidia]

Re: does this sound right? 43mph from a 50hp?

I have a 2007 40 Merc 4 stroke. I can clock around 36 mph when alone. My rig is 14.9.

Your speed sounds in the ballpark to me for a 50 depending on the right prop and height of the cavitation plate. If yours is a 2 stroke which is lighter than most 4 strokes then 43 mph sounds even more on target especially if you are clocking with a GPS which can be more accurate than some old Speedos.

 

[Dave1027]

Re: does this sound right? 43mph from a 50hp?

Definitely check it with a GPS. My speedo reads high. Most boats I have ridden in also read fast.

 

[flyinbryan]

Re: does this sound right? 43mph from a 50hp?

Post up the serial number and we can check it for you. Also a photo of the engine would help.
Chris.......

that would be great! od195683,,,,,,,,,,,dont have any pics, but i will take some this weekend and postum in this thread.

i get 40 - 43 mph on my 15'5 sangster flat bottom with just myself in it . and i have an 88 classic fifty ( 45hp) 4cyl. with a SS prop

Yep.. All the 40/50/60 (3 cylinders) from 1991 till about 2007 have the WME carbs and variable oiler...

I have a 2007 40 Merc 4 stroke. I can clock around 36 mph when alone. My rig is 14.9.

Your speed sounds in the ballpark to me for a 50 depending on the right prop and height of the cavitation plate. If yours is a 2 stroke which is lighter than most 4 strokes then 43 mph sounds even more on target especially if you are clocking with a GPS which can be more accurate than some old Speedos.

yep, id have to say it sounds about right then. i did have a 1984 force 50hp way back when, on a 14ft bayliner, and that one would only run about 27-30mph, so i remember how surprised i was when my new (back then) 50 merc was so much faster.

Definitely check it with a GPS. My speedo reads high. Most boats I have ridden in also read fast.

thats a good point. i did run it against my brother in laws bayliner that has a v6 i/o, and it was a dead even race, and he said his only ran 41 on gps, so mine might actually run only 41mph. (but i did have my nephew in the boat with me that day)

this site is the best resource ive ever seen for fellas who like water toys.

thanx guys, bryan.

 

[achris]

Re: does this sound right? 43mph from a 50hp?

that would be great! od195683,,,,,,,,,,,dont have any pics, but i will take some this weekend and postum in this thread....

Definitely comes up as a 50hp.... 1993 ELPTO

If you post the prop pitch and diameter and the revs and speed at full noise I'll plug them into my prop calculator and see what it says....

Chris........

 

[flyinbryan]

Re: does this sound right? 43mph from a 50hp?

i could be wrong, but i think the prop is a 16 pitch by michigin wheel. not sure on the diameter.

rpm in the 5400-5600 range.

 

[achris]

Re: does this sound right? 43mph from a 50hp?

I plugged in the numbers 10"x16", 37knots at 5500 revs (your gear box ratio is 1.64:1) and they didn't look to good. So I put in the prop as a 14" and they look fine. Just re-check your prop when you have time, but 37 knots doesn't sound unrealistic.

You may also want to (read: "I seriously recommend") download the proper Merc manual for your engine and use the clymer for hand towels.

Click HERE to download, the password is <ribforum>.

Chris........

 

[flyinbryan]

Re: does this sound right? 43mph from a 50hp?

hey achris, ive tried to download that but i guess i aint too good at this computer downloading stuff.

it says i cant open it after ive downloaded it. i also dont see anywhere to use the password, it just gives me a free option to download, but then it doesnt work.

 

[achris]

Re: does this sound right? 43mph from a 50hp?

PM me your email address and I'll email it to you... It's only 15Mb so it shouldn't take long....

 

[flyinbryan]

Re: does this sound right? 43mph from a 50hp?

PM me your email address and I'll email it to you... It's only 15Mb so it shouldn't take long....

awesome man, cant thank you enough.

pm enroute.

 

[flyinbryan]

Re: does this sound right? 43mph from a 50hp?

i never knew there was a more accurate service manual to be honest.

so far the biggest pain ive encountered with the clymer was the oil injection output test, because the first variable oil injection system overview (smallest motor size that uses it) in their book is the 75hp motor.

(not that i ever needed to do the test, but still it was strange to me that they didnt have it right)

 

[achris]

Re: does this sound right? 43mph from a 50hp?

.... but still it was strange to me that they didn't have it right)

That's the world of after-market....