If alignment is off just a little...

[liquidlew]

Just had my drive off for the first time and replaced the gimbal bearing (bearing was a little rough), popped in the alignment tool and noticed my alignment is off a bit, so it ran like that all last year (actually the last 4 years since I got the boat, and yeah, I know, I'm supposed to remove the drive yearly!). Could that be a possible reason why I still don't get close to my RPM range? The range is 4400-4800, and at best I top at 4100 with fresh tune up, practically new everything, numerous props, and only me in the boat. Compression is good, had heads done 2 years ago also. Going to get the alignment straightened out today...I don't know what else could be keeping me from getting into that range?

 

[z1nonlyone]

Re: If alignment is off just a little...

Just had my drive off for the first time and replaced the gimbal bearing (bearing was a little rough), popped in the alignment tool and noticed my alignment is off a bit, so it ran like that all last year (actually the last 4 years since I got the boat, and yeah, I know, I'm supposed to remove the drive yearly!). Could that be a possible reason why I still don't get close to my RPM range? The range is 4400-4800, and at best I top at 4100 with fresh tune up, practically new everything, numerous props, and only me in the boat. Compression is good, had heads done 2 years ago also. Going to get the alignment straightened out today...I don't know what else could be keeping me from getting into that range?

Not in my opinion! If the missalignment was sucking up that much HP, the bearing would not last long at all and would almost certainly overheat the bearing!!!

 

[liquidlew]

Re: If alignment is off just a little...

Thanks for the replys! I don't think it is off by much, the bearing was just very slightly rough, I could feel it but 2 of my pals said they couldn't feel it. It otherwise spun freely. The alignment tool goes in fairly easy with just a slight resistance, but this is my first time so I'm gonna keep doing it till I'm sure I'm doing it right before I put the drive back on.

 

[TyeeMan]

Re: If alignment is off just a little...

If the boat is the same as in your signature you have point and condenser ignition right? My 89 3.0 has points, , , any way check your counter weights in the distributor. If they're rusty they may not be flying out as far as they should, ie your not getting maximum timing advance so you wont realize your top rpm.

 

[liquidlew]

Re: If alignment is off just a little...

If the boat is the same as in your signature you have point and condenser ignition right? My 89 3.0 has points, , , any way check your counter weights in the distributor. If they're rusty they may not be flying out as far as they should, ie your not getting maximum timing advance so you wont realize your top rpm.

No, I have the 4.3 with Thunderbolt ign. No points or condenser. My timing is dead-on and everything else is in tiptop shape. I noticed on the side of my drive the #1.50 stamped in front of the drive s/n, so I'm assuming that is my gear ratio? Drive # is OD628960, that # is not listed in my Merc #6 manual, so maybe the PO changed the drive at some point? It is still a Gen 1, still has the old style water pump/impeller. So maybe I need to go even smaller pitch on the prop? Lowest pitch I tried was 17p.

 

[muc]

Re: If alignment is off just a little...

That?s a 1991 drive built as a 1.50 ratio.
Might not be able to get the right R.P.M.s with a prop change.
Good Luck Muc

 

[cr2k]

Re: If alignment is off just a little...

I was wondering why my 3.8 didn't get near the wot RPMs it should have until I looked at the back of the tach and it was set to 8 cyls. Something to check.

 

[liquidlew]

Re: If alignment is off just a little...

I was wondering why my 3.8 didn't get near the wot RPMs it should have until I looked at the back of the tach and it was set to 8 cyls. Something to check.

Didn't know about that, I will poke my head up in there today and check that out, thanks!
According to the manual, I'm supposed to have a 1.84 gear ratio, the PO I got the boat from was an avid skier, but he was a big guy (250 ish lbs.), so that makes sense, he probably changed it to 1.50 so the boat could pull his carcass out of the water, or he wrecked the original drive, or both...