Lower Unit Slipping? Need advice and help.

[DamianJP]

Hello

Motor is a 1989 150 XR4 with the stock L/U that came with the XR4's.

When I get to a certain speed , take a hard enough turn , or trim the motor too high
I would lose speed and and have abit of RPM loss. I thought it was the prop spinning due to a spun hub. I etched a line into the prop and the hub part and took her out to reproduce the symptom. Came back in and noticed that the line was still lined up. There is no way in hell it could of lined back up. Whats my next move?

Iv'e had the boat for about 4 years and never had the L/U worked on, or sealed.

If the L/U is slipping or needs works I want to get the L/U done %100.

How much should it be to have the whole lower unit rebuilt and sealed? Ballpark.


Thanks,
DamianJP

 

[jerryjerry05]

Re: Lower Unit Slipping? Need advice and help.

Sounds like it's a handling problem.The lower won't slip.It will cavitate if too high on a turn or too high in the water when your accelerating to fast.
When taking a hard turn at high speed u need to lower the motor a bit to keep it biting clean water. Too high and it will slip/cavitate.
Is the steering fin on right?Does it pull hard to the right or left?
Is the motor running right?Do a comp/spark test.Then rebuild the fuel pump.Replace any inline connectors.It could be sucking air under a load.Finish the profile.U might be close to someone who can help.J

 

[DamianJP]

Re: Lower Unit Slipping? Need advice and help.

Hey Jerry

It seems like I can't trim the motor as high as I used to. I just re did the carbs and fuel pump, havent done a spark/comp test in abit, will do next.

I have a hydro foil fin on it aswell.

She just doesn't seem to 'grab' the way she used to. Even in a straight line just seems like somethings not right.

Does not pull hard to right or left.

I use to be able to get more of the boat outta the water trimming it up and she used to run like a scalded dog on the pad only, now I gotta baby the throttle and trim more often. I'll check for a air leak in the fuel line(s) and all around.


Thanks,
DamianJP

 

[j_martin]

Re: Lower Unit Slipping? Need advice and help.

They don't slip. They either pull or self destruct. Take the oil drain plug out and catch the first few drops of oil. If it's not milky or full of metal chips, yer OK. If it's black and dirty, change it. Use the Mercury Hi-perf lube in it.

It doesn't take much of a ding on a prop to make this hot rod skip out of the lake. Another thought is transom rot letting the engine tilt different than you're used to. Don't ask how I know that one.

What's with the whale tail? Is that thing on a tuna boat or something?

 

[DamianJP]

Re: Lower Unit Slipping? Need advice and help.

Hey Jmartin

Whats the easiest way to do a spark test on this motor?

Hopefully it's not transom rot, I can't tell if its flexing when going at that speed. I dont think the transom is that bad. How can I tell if its in bad shape? You would think if the transom was flexing that much, the motor would rip off by now.

Picked up the hydro fin to give me lower planing speeds, less bow rise when planing . You think it might be causing the problem? Though Iv'e had it ever since I had this rig.


Thanks,
DamianJP

 

[jerryjerry05]

Re: Lower Unit Slipping? Need advice and help.

The motor if it has T+T wasn't designed for an extra fin.Some help a bit some don't work.The only time I saw one work was on an 8hp Honda on an inflatable.Take it off.
As far as the transom,lower the motor about half way.Then go shake it up and down see if it moves.What condition is the prop?Is it stainless?Older aluminum actually wears down.My father had a whaler with an OLD(1960's) 65 Johnson.He was complaining about how it wasn't runninng as good as it used to..We got to looking and he measured the prop and over the years it had worn down about 3/16".Lots of things to look at.J