can't plane after engine swap. does reach 5000 rpm's

[grewvin1]

Re: can't plane after engine swap. does reach 5000 rpm's

Just dropping in here, this is one of the best mysteries in awhile when you get this figured out you must let us know the cause and fix.

 

[achris]

Re: can't plane after engine swap. does reach 5000 rpm's

The drive was never removed....

Is that an engine coupler I can smell burning up?

 

[ktbarrentine]

Re: can't plane after engine swap. does reach 5000 rpm's

Who swaps an engine without dropping the drive??? I just don't think it is possible. :facepalm:

 

[TilliamWe]

Re: can't plane after engine swap. does reach 5000 rpm's

Who swaps an engine without dropping the drive??? I just don't think it is possible. :facepalm:

It is possible, but why you would want to do it is beyond me! I have read on here time and again where people act as if they are afraid to remove the outdrive. And I always say, "it'll be the easiest part of the whole job (engine change)."

 

[achris]

Re: can't plane after engine swap. does reach 5000 rpm's

It is possible, but why you would want to do it is beyond me! I have read on here time and again where people act as if they are afraid to remove the outdrive. And I always say, "it'll be the easiest part of the whole job (engine change)."

Yep, 3 minutes!

 

[onebadbusa]

Re: can't plane after engine swap. does reach 5000 rpm's

Yep, 3 minutes!

my friend has been swapping motors in boats for years both personally and professionally. The motor was disconnected and pulled out in under an hour and it was put in the same way. Drive left in place. Bucket loader and chain. Slid right in after turning the prop a hair and bolted up. No smells, leaks or anything out of the ordinary. I did have trouble timing it. Would only reach 4800 and top speed of 14. After advancing the timing 38 degrees it now reaches 5000 rpm but will not plane out.

 

[achris]

Re: can't plane after engine swap. does reach 5000 rpm's

my friend has been swapping motors in boats for years both personally and professionally. The motor was disconnected and pulled out in under an hour and it was put in the same way. Drive left in place. Bucket loader and chain. ...

Bad idea, very bad idea! You have no idea what the alignment is like. The coupler doesn't fail or 'smoke up' immediately, but fails over a period of time. You run the risk of destroying the coupler and the yoke....

Pull the drive now and check the alignment, or you will be pulling it again anyway to replace expensive parts that you could have saved....

Chris......

 

[TilliamWe]

Re: can't plane after engine swap. does reach 5000 rpm's

my friend has been swapping motors in boats for years both personally and professionally. The motor was disconnected and pulled out in under an hour and it was put in the same way. Drive left in place. Bucket loader and chain. Slid right in after turning the prop a hair and bolted up. No smells, leaks or anything out of the ordinary. I did have trouble timing it. Would only reach 4800 and top speed of 14. After advancing the timing 38 degrees it now reaches 5000 rpm but will not plane out.

Anyone remember Jeff Goldblum's response to the quote in the second Jurassic Park movie where the old man says, "we won't make the same mistakes this time."? It applies here, I think.

 

[achris]

Re: can't plane after engine swap. does reach 5000 rpm's

Anyone remember Jeff Goldblum's response to the quote in the second Jurassic Park movie where the old man says, "we won't make the same mistakes this time."? It applies here, I think.

Yep, we're making all new ones....

 

[Bondo]

Re: can't plane after engine swap. does reach 5000 rpm's

my friend has been swapping motors in boats for years both personally and professionally. The motor was disconnected and pulled out in under an hour and it was put in the same way. Drive left in place. Bucket loader and chain. Slid right in after turning the prop a hair and bolted up. No smells, leaks or anything out of the ordinary. I did have trouble timing it. Would only reach 4800 and top speed of 14. After advancing the timing 38 degrees it now reaches 5000 rpm but will not plane out.

Ayuh,... As noted, the motor has to be aligned to the gimbel bearing,...

Ya also can't properly service the drive, unless ya Pull it off...
6 nuts, 2 pin locks, 'n 5 minutes to pull it...

 

[onebadbusa]

Re: can't plane after engine swap. does reach 5000 rpm's

Ayuh,... As noted, the motor has to be aligned to the gimbel bearing,...

Ya also can't properly service the drive, unless ya Pull it off...
6 nuts, 2 pin locks, 'n 5 minutes to pull it...

I remover the mounts from the original motor which was professionally aligned and installed them exactly the way they came off not touching the adjustment bolts. This wound insure proper alignment.

 

[Don S]

Re: can't plane after engine swap. does reach 5000 rpm's

I remover the mounts from the original motor which was professionally aligned and installed them exactly the way they came off not touching the adjustment bolts. This wound insure proper alignment.

Doesn't really mean much if the bolt holes in the block were machined in a slightly different location on the new engine.

You can make all the excuses you want, but when you replace an engine or even take it back out and put it back in, things can change.
That is why you always check the alignment before installing the drive.
It also makes it a lot easier to get the motor mount hardware in place when you can just sit straight down in it, instead of lifting and flexing the coupler in order to get above the hardware when installing.
It's your coupler, and you've been warned that things could be out of alignment and you should check it. Rather you do or not is up to you.

 

[onebadbusa]

Re: can't plane after engine swap. does reach 5000 rpm's

Well it's finally here (Spring) and I uncovered the boat. I met a boat mechanic Saturday morning to check the alignment on my motor hoping it would be off and I could finally enjoy my new motor but it was not to be. The tool went in and came out with grease evenly spread around it. Not sure what is left to rule out the problem. I am going to adjust the linkage on the carb to give me a little more RPM's whne I launch in a few weeks.

Doesn't really mean much if the bolt holes in the block were machined in a slightly different location on the new engine.

You can make all the excuses you want, but when you replace an engine or even take it back out and put it back in, things can change.
That is why you always check the alignment before installing the drive.
It also makes it a lot easier to get the motor mount hardware in place when you can just sit straight down in it, instead of lifting and flexing the coupler in order to get above the hardware when installing.
It's your coupler, and you've been warned that things could be out of alignment and you should check it. Rather you do or not is up to you.

 

[funk6294]

Re: can't plane after engine swap. does reach 5000 rpm's

Bussa, have you tried putting a mark on the coupler housing and one on the drive shaft to ensure that the coupler is not slipping?

 

[sweet addiction]

Re: can't plane after engine swap. does reach 5000 rpm's

Bussa, have you tried putting a mark on the coupler housing and one on the drive shaft to ensure that the coupler is not slipping?

I have read every post on this thread...I agree with funk. I had a drive couple go bad once and never smelled a thing when it happened. All of a sudden the RPMS went up and my speed was lost. I bet the Drive couple was already on it's last leg before the engine swap.

 

[cecho]

Re: can't plane after engine swap. does reach 5000 rpm's

Could exhaust gas around the prop cause cavitation that would allow the engine to rev high?

 

[fishrdan]

Re: can't plane after engine swap. does reach 5000 rpm's

I met a boat mechanic Saturday morning to check the alignment on my motor hoping it would be off and I could finally enjoy my new motor but it was not to be.

I don't think anyone was suggesting that aligning the engine was going to cure your speed issue. The alignment just needed to be checked/verified so the coupler didn't get torn up and create other problems.

You mentioned changing props, what was their pitch, diameter, aluminum, stainless???

 

[Radarman68]

Re: can't plane after engine swap. does reach 5000 rpm's

Something else to consider is this sounds like the engine is hitting the rev limiter. Not to mention, it is several hundred RPM OVER maximum recommended RPM. IIRC, 4800 is the maximum rated RPM for the 5.7.

this means you are not putting sufficient or expected load to the engine. this means mechanically, not all the power is getting to the water. there are only a limited number if things that can do this and folks have done a good job listing them so far. I would not look at the engine any more. (on edit) The problem exists either between the flywheel and propeller, drive trim, or boat weight/drag.

 

[QC]

Re: can't plane after engine swap. does reach 5000 rpm's

Could exhaust gas around the prop cause cavitation that would allow the engine to rev high?

This could be "ventilation", but he is using the same prop and the same drive, so unlikely this has been introduced by the engine change.

 

[fossill]

Re: can't plane after engine swap. does reach 5000 rpm's

obviously the 5000rpm (if that's what it's actually spinning at) from the crank isnt making it to the outdrive,