Atomic 4 and standered prop reverse

[RJ1946]

Hi, I'm a fairly new owner of a C30 with Atomic 4 and was wondering if all atomic 4 C30's are as slow and week in reverse as mine, or if I have a problem. If it is a common characteristic is there anything that can be done, or tricks to using reverse.
Any help would be really appreciated
Thanks

 

[Old Skool Neil]

Can you describe the sound made when in reverse? It would help in determining if you have a problem at all.

 

[Team118]

I have a 77 Catalina 30 with the Atomic 4. It certainly doesn't have the umphf in reverse. I've noticed that as my speed picks up in reverse, the rudder begins to shimmy because it is in front of the boat and any flow across it's wingform forces it one way or the other.

Other than that, reverse is all about getting out of the dock or setting the anchor, situations that don't seem to require 100hp Merc speed...

 

[Photo Bug]

Yes they all are slow in reverse. I don't remember the correct ratio but the prop turns either 1/3 or 1/2 the normal revs when it is in reverse. Go to Moyer Marine to find more information. www.moyermarine.com/

 

[RJ1946]

Niel2099, Doesn't make any strange sound, engine revs and can't feel any response from boat for a few minutes and the response is just really slow. Really hate to have to make an emergency stop

 

[cat30]

the atomic 4 has a different trransmission ratio in reverse- you have to crank up the rpm's to get the boat to move in reverse.

 

[Old Skool Neil]

I'd say you're not in reverse or it's really slipping.

The Atomic 4 reverse makes an obnoxious and unmistakable grinding gear noise, like granny low on Grandpa's old F-250 manual shift pickup truck. I mean it really howls. Also, there's no shift feel into reverse, no clunk. It kind of leans into reverse.

I didn't mention the noise in my question to you hoping to read about it in your response. The absence of the noise tells me your either not reversing or very poorly.

It is likely a simple adjustment of maybe the shift linkage, the transmission or a loose shift cable. And I can't emphasize this enough, join the Moyer Marine site, this is thoroughly discussed in the community forum archives. The forum is question friendly too. Everybody there is immensely helpful, no ego trips, a great place for newbies and experienced users.

 

[RJ1946]

Thanks Niel I'll check Moyer

 

[Twice Around]

RJ1946, I am a member over at the Moyer forum as well. I was new to A4's about 18 months ago...that site is great.

Look forward to chatting with you about your boat..Neil's got the reverse thing right...I lean on my shifter to keep it in gear...it has a 'brake band' that grabs the gearing but you need to hold it.

 

[Mark J]

Love my A4. Just finished a pan up rebuild on a 1977. learned alot about via Moyer Marine's forum, and overhaul manual and phone conversation with Ken from Moyer. He rebuilds engines and is very helpful. I bought all my parts through them, had the block and head done at local machine shop to include a bore out in cylindars. Ran it on the bench and checked the reverse action. still screams at you but when you watch the shaft you can really see the reverse engage and shaft turn. anticipating some good HP out of it now.

 

[Mark J]

http://www3.sympatico.ca/atomic4servicemanual/
If you don't have a good service and repair manual for the Atomic 4 Marine Engine, I recommend you go to this site and order this service manual. It has a good section on the transmission and reduction drive.

 

[RJ1946]

Thanks for the information. When it is forward I get a lot of noise, sounds like an old washing machine, in reverse I don't get the noise, the shaft is rotating, and eventually reverse does work.

 

[Old Skool Neil]

The normal A-4 noises are quiet in forward and howling in reverse. Your noises suggest the gearbox isn't functioning properly.