What Would Cause This...

[Jason2tpa]

'98 S115TLRW

Cruising back to the boat ramp this evening, calm seas, running about 4200 rpms. Out of nowhere the engine lost power while simultaneously sounding as if the rpms were winded out. It happened so quickly, and my response to pull throttle back into neutral was so quick, I did not look at what the rpms were during this sudden event. All of this occurred in less than 2 secs.

I sat idling in neutral for a moment, idling fine, normal rpms. I cut engine, trimmed up and checked prop. Good. Started up again and throttled up to the rpms I was at when this happened. Ran it at 4200 for about a minute and by that time I was at the boat ramp. I was not in shallow water when this event occurred, so no chance of the prop contacting a ground.

My first thought was maybe some fishing line was wrapped, then cut loose. I don't know. What would cause what I've described above? If this was a sign of something beginning to fail I want to be on top of it.

[panasonic]

My guess is your prop picked up something, plastic bag, seaweed, weeds, something like that and lost its water (cavitation) By the time you chopped the power and had a look it was gone.

This has happened to me many times while running in a area where there was very long kelp growing almost to surface and hitting it while going fast. Sometimes it would stay wrapped around the prop, other times it would be gone by the time I had stopped and checked the prop.

I would not worry about it too much unless it keeps happening. Then it could be a case of the LU popping out of gear....but I think not likely.

[99yam40]

never hurts to mark the prop and hub, then if it happens again you can look to see if the hub spun

[DennisG01]

Agree with the above - most likely culprit is you momentarily picked something up that wrapped itself around the lower unit, causing ventilation to the prop. Seaweed, etc. Have had this happen many times. Often times, it doesn't fall off by itself when I power down so I pop it in reverse for a few seconds and that clears it.

It could be something else, like a hub starting to spin, but based on what you wrote the above scenario is the most likely.

[Jason2tpa]

Appreciate all the input. Now I think about it, there was a significant amount of seaweed in the water last night. Strong outgoing tide. It could of been the cause.

Walk me through marking the prop and hub like 99yam mentioned. Where do I mark and what am I looking for after running the engine next time I'm on the water?

[Jason2tpa]

(actually, I thought you just got a new prop??)

I recently tested a lower pitch prop. It did not have an acceptable result.

[Jason2tpa]

Got it, thanks!

[pstephens46]

And if it slips, it should get worse with time.

[Jason2tpa]

Whelp, I recon I found the reason why I experienced the abrupt power loss with high rpms. I did mark the hub and nut before testing. Results were the marks are about 90º off. Pulled off the prop and this is what I discovered. The prop shaft was covered with pieces of rubber and the hub itself I could scrap off rubber with my finger.

Other than this most recent event there were no indications of slippage, so it looks like I caught it early.

[99yam40]

should be able to find a prop shop( machine shop) close to you to press in a new hub, or your local boat dealer will know were to send it.

Last one I had done cost was about $60, probably a lot more now a days.

a lot of the newer props have owner replaceable hubs.
but you have the one that needs a press

[Jason2tpa]

should be able to find a prop shop( machine shop) close to you to press in a new hub, or your local boat dealer will know were to send it.

Last one I had done cost was about $60, probably a lot more now a days.

a lot of the newer props have owner replaceable hubs.
but you have the one that needs a press

How can you tell it's a press in hub requiring a prop shop removal?

[99yam40]

if it slips apart easily ,it does not need to be pressed apart and back together.
yours is a press hub

[Jason2tpa]

if it slips apart easily ,it does not need to be pressed apart and back together.
yours is a press hub

I think I gotcha...so if it's a press in hub it requires a special device that pulls the hub out? I can't imagine the service of pressing the hub out by a prop shop is difficult or take long to do. You have an idea of what this service cost is...$20-$30?

Also, I was eyeballing the flo-torq II hub as the replacement, which can be installed by the user. Does it matter the hub installed now is a press in and the replacement not be? All my years owning boats this is my first spun prop, so bear with me if this seems remedial.

[99yam40]

should be able to find a prop shop( machine shop) close to you to press in a new hub, or your local boat dealer will know were to send it.

Last one I had done cost was about $60, probably a lot more now a days.

a lot of the newer props have owner replaceable hubs.
but you have the one that needs a press

just in case you did not read my post from before
also this was on a 35 hp motor, yours maybe close to $100 , call a shop and ask

the prop itself is different for the owner replaceable hubs
I now have a Michigan Wheel Ballistic prop with the XHS hub system that I can change myself

[99yam40]

Yes I did.

Always read prior posts (may miss something in them BUT do read them).

*Just confirming your post, that Jason's thought of $20-$30 isn't realistic.

actually I was asking Jason, since he asked about price