Idles Great but No Power

1979 Merc 115 6 cyl. Starts and idles great. No power at all in gear. Motor will "rev" up over 4-5k in neutral and sounds good. Seems like ignition/timing issue. Any ideas?

Re: Idles Great but No Power

Need some history. Did you buy it that way?. Did it suddenly, or gradually get that way? What's it mounted on?

John

Re: Idles Great but No Power

Scott, Don't rev it up high in neutral. It proves nothing, and it could blow up.

Answer John's questions and we can go from there.

Re: Idles Great but No Power

Thanks.

Motor is on 18ft Starcraft Holiday. UNfortunately, I have zero history. This was the first run on the water. Compression is good on all 6. I guess I was starting with the assumption that it was not fuel since the motor idles well. Was leaning towards an ignition issue but have no idea where to start. I did find the cdi trouleshooting guide online...i was hoping to get some suggestions here. Any help would be appreciated!

Re: Idles Great but No Power

John, Chris, I'm thinking fuel filter, maybe pump what about you. Of course the basic checks need to get done first.

Re: Idles Great but No Power

We just noodled out this problem on a V6. Turns out the flywheel had been disassembled and put back one bolt off.

Good compression is a plus. Anything else can be fixed.

First thing would be to get a shop manual, preferably genuine murkery for it. Do the linkage and timing adjustment in the book. Then we can start considering symptoms and circumstances.

If fuel is questionable, it's best to throw it out and start over. Same with the fuel filter.

Don't rev it over a coupla grand unless it's pushing a boat. If it should happen to run away, it could grenade in a heartbeat.

If it's been store awhile, or been dry fired, change the water pump impeller right away.

hope it helps
John

Re: Idles Great but No Power

Gotcha. No more rev-ing.

1. new fuel/lines in a clean tank. I do need to run through the fuel system though.
2. Get a REAL service manual and do link/timing (where to find one?????????????????)
3. write back for help from you all

Thanks

Re: Idles Great but No Power

scott hamilton said:

Gotcha. No more rev-ing.

1. new fuel/lines in a clean tank. I do need to run through the fuel system though.
2. Get a REAL service manual and do link/timing (where to find one?????????????????)
3. write back for help from you all

Thanks

Click to expand...

#2 look up your serial number on either mercurypartsexpress.com, or mercruiserpart.com. Service manual is in the parts list.

hope it helps
John

Re: Idles Great but No Power

When you get your service manual see if you can get the ammendments and service notes also. I know on my 1991 they changed the recommended stator and the WOT timing in 1996. Mine had the upgrade but I was using the original specs. Didn't make any difference though, it still runs like poop. LOL.. Best of luck and happy hunting!