1998 115 OB Mercury slips out of gear

[Walliwally]

I can idle forward and reverse fine, but when I punch it down it starts to take off, then the engine over-revs and the prop quits turning as if it is slipping out of gear.

I checked linkage etc., and all seems fine.

Tightened Prop and checked hub...seems fine.

I didnt try real hard in reverse, but doesnt seem to do it.

Not sure if its related or not, but also dont have any water coming out of the "pisser".

And another wierd and seemingly unrelated thing, I show 18+volts on the meter (never has before)..almost pinned.

Any help at all would be much appreciated.

 

[achris]

Re: 1998 115 OB Mercury slips out of gear

It sounds like you may have spun the splines out of the bottom of the crankshaft. This is bad... Do you have water coming out of the telltale when the engine is running at idle, and only loss it when it 'pops out of gear'?

Chris......

 

[CharlieB]

Re: 1998 115 OB Mercury slips out of gear

When it acts like it is slipping and you pull the throttle back to idle, but still in forward gear, is the prop still turning and slowly pushing the boat?

Make the hub and shaft, put it in forward gear, engine OFF, on the trailer, STAND on the prop, can you make it slip?

If it is not a slipping prop, if it is clunking in and out of gear, then it may be time to replace your stretched shift cable.

 

[PJSuburby]

Re: 1998 115 OB Mercury slips out of gear

I have the same engine, but have not had that problem.
Pull the cowl off and check that the shift cable pulls the shift linkage ALL the way when you shift forward. The cable may not be moving linkage enough to fully engage. Easy to check and easy to adjust. Good luck.
I just replaced shift and throttle cables. Easy to do also.

 

[achris]

Re: 1998 115 OB Mercury slips out of gear

Hey, y'all,

He's got no water from the telltale! How does an incorrectly adjusted shift cable cause that?????? Crankshaft splines!!!!!!!

Chris.........

 

[Walliwally]

Re: 1998 115 OB Mercury slips out of gear

Thanks everybody...I appreciate all the help.

Update. I drove it about 4hrs (long story, but short version is I had to for a 80th b-day party).

Checked cables, all ok.

If I accelerate extremely slowly, I can feather it up to about 30mph, but it takes the whole lake.
Up to between 2500 and 3000 rpm it stays in gear, but if I try to get there too quick, it "slips" and I have to start all over again.

I do not have to pull it all the way out of gear. Once it tachs down to about 1000 rpm, it "catches" again.

Any requirement for extra power (more people in the boat, etc.) and it slips sooner.

It shifts into forward and reverse solidly and it appears like I could idle around the lake all day if I want.

Spline theory seems to be the most plausible..thanks achris!!

Also, I still have no water coming out the telltale, but it didnt overheat, and my voltmeter still reads over 18 volts most of the time, yet the battery didnt blow up.

Again, many thanks to everyone.

 

[PJSuburby]

Re: 1998 115 OB Mercury slips out of gear

Well, You have to follow up with this thread and let us know what it was.
Hope you rule out ALL the simple things before attacking the engine guts. Seems to be the wisest move.
Good Luck!

 

[CharlieB]

Re: 1998 115 OB Mercury slips out of gear

Two seperate problems

1 Slipping prop hub, holds at low power/throttle, slips once power is increased, try another prop, then send this one in to replace the hub.

2 Tell-tale plugged, run a small wire up into it to clear or blow into it with an air hose.

 

[Walliwally]

Re: 1998 115 OB Mercury slips out of gear

Already a brand new hub and prop

 

[CharlieB]

Re: 1998 115 OB Mercury slips out of gear

What STYLE hub, too many times the partsman sold the WRONG hub kit with a good prop.