2005 merc 9.9 some questions

[dkonrai]

just wondering if the motor sounds like its running right.
boat, 14 foot gregor (about 230 pounds) kid and i (another 350 or so) tackle, cooler, 6 gallons of fuel, 10 pound anchor. we topped out at 20 or so per the gps.
does this sound about right? only asking as i am pretty much a omc guy and my 9.9 johnnyrude does about 25 or so.

a vid of the motor running. it does run quite and i didnt use any gas at all fishing.
merry christmas!
thanks
dino

 

[Bob_VT]

Re: 2005 merc 9.9 some questions

Looks Okay....... maybe a prop change? Hard to tell. Why not invest in a tiny tach and see what the WOT rpms are and go from there.

 

[tpenfield]

Re: 2005 merc 9.9 some questions

It does not sounds like it is reaching a high enough RPM . . . but that is just from the sound.

Here is my old 7.5 hp for comparison.

You may want to check to see if the throttle linkages are set properly, etc.

 

[Sea Rider]

Re: 2005 merc 9.9 some questions

Running right is a ambiguous statement, will depend on boat's passenger balance, correct trim, correct prop for that application, best engine height and water conditions. If it's 20 knots, i'd say excelent for a 9.9 and asssuming gps was working properly-

Install a Hardline hour/tach and check max achieved rpm at full wot, then you can play with prop pitches to maximize full 9.9 power out of that engine. BTW you can pass that 9.9 into a 15 HP...

Happy Boating

 

[steelespike]

Re: 2005 merc 9.9 some questions

The 4 stroke will usually "seem' like the rpm sounds lower than a 2 stroke at the same speed. Thats because there are 1/2 as many power strokes. The 4 st. hole shot may be slightly slower than the 2 stroke.
I think your speed is really close to normal especially considering your load.
Its highly unlikely your old 9.9 made 25 with the same load. Assuming a 10" prop that would require about 7200 rpm.It's unlikely it could make that with the standard 10" prop.
It likely had better hole shot and sounded faster.The little Johnnyrudes do rev freely but the pre 89 motors were rated at 6,000 and 89 on were rated at 6500 max.
My rule of thumb for a lightly loaded 9.9 is 20-21 mph.

 

[dkonrai]

Re: 2005 merc 9.9 some questions

Looks Okay....... maybe a prop change? Hard to tell. Why not invest in a tiny tach and see what the WOT rpms are and go from there.

bob,
good call. i never actually bought a tiny tach. but it looks like i may be buying another toy

 

[dkonrai]

Re: 2005 merc 9.9 some questions

nice running merc you have there. this is the first 4 stroke (well i did have two others...) that is close to new. the other a honda 87/10hp, and a johnson 96/15hp (never ran the johnson on the water traded the johnson for this merc) honda ran ok but it was a dog out of the hole.
dino

 

[dkonrai]

Re: 2005 merc 9.9 some questions

Running right is a ambiguous statement, will depend on boat's passenger balance, correct trim, correct prop for that application, best engine height and water conditions. If it's 20 knots, i'd say excelent for a 9.9 and asssuming gps was working properly-

Install a Hardline hour/tach and check max achieved rpm at full wot, then you can play with prop pitches to maximize full 9.9 power out of that engine. BTW you can pass that 9.9 into a 15 HP...

Happy Boating

?? 9.9 into a 15??? talk to me

The 4 stroke will usually "seem' like the rpm sounds lower than a 2 stroke at the same speed. Thats because there are 1/2 as many power strokes. The 4 st. hole shot may be slightly slower than the 2 stroke.
I think your speed is really close to normal especially considering your load.
Its highly unlikely your old 9.9 made 25 with the same load. Assuming a 10" prop that would require about 7200 rpm.It's unlikely it could make that with the standard 10" prop.
It likely had better hole shot and sounded faster.The little Johnnyrudes do rev freely but the pre 89 motors were rated at 6,000 and 89 on were rated at 6500 max.
My rule of thumb for a lightly loaded 9.9 is 20-21 mph.

ok i see, im so used to the 2 strokes running higher revs and most definitely faster out of the hole. i think this little motor tops out at 4 or 5000? much lower than 2 strokes for sure. omg it is quite and sippy on the gas. i still have a full tank after fishing the whole day.

dino

 

[steelespike]

Re: 2005 merc 9.9 some questions

Actually the rated rpms are similar. the merc is 5000 to 6000 the 89 up E/J is 5500-6500. They both have a 1000 rpm range
the Evinrude just starts 500 higher.The earlier E/J 9.9s were 5000-6000. You'll find that on bigger motors many times the rpm of a 4 stroke is higher.
Regardless of the rating generally the 4 stroke, to the ear, will be percieved at lower rpm.