Boat motor acceleration issues.

[mattybculp]

Hello all, I know there are some mechanically inclined people on this forum however I am not one of those individuals. I was heading down Indian river off of rice last night. We were puttering along nice no problems and then I would go to accelerate and the rpm's would increase however at a certain threshold it would just seem as though the prop wasn't spinning, it was ok to putter along at 3-4 mph but the moment any more throttle was given a lot of commotion would happen but no speed. It's a 2008 70 yammy. It's always run like a top other than then regular maintenance it has never had an issue. Does this sound like a spun hub to you ? Is there something I can do to check what it may be. ? What's involved to correct the issue and is it an expensive fix. ?Thanks for any input. You folks are great. Ps no eyes last right on rice only one crappie and a small tiger.

[John Bacon]

I think the spun prop hub is the mose likely cause.

 

That shouldn't be too expensive if you are running an aluminum prop. I paid just over $100 for a rebuilt prop for a 50 hp Mercury.

[Garnet]

Look at the nut area and hub for little curly tails rubber or plastic. Takes a pro to fix or buy new.

[Sinker]

You didnt just have weeds around the prop did you?

 

S.

[mattybculp]

Thanks for your replies. Shane, no as soon as it happened I was coming in just past foley island towards Indian river where it gets shallow and I noticed some floating weed and I though the same thing. Gave her a shot of reverse the result was the same so i trimmed up the motor to have a look and sadly no weeds. So if it was a spun prop does that mean replacing the prop or have it rebuilt.? And i made a mistake in my earlier post it's a 75 hp yammy.

[lew]

Matt, take it up to Buckhorn Yacht Club and let them have a look at it. Their probably the best prop guys around here and will tell you exactly what's going on.

 

https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CDYQoAIwAg&url=http%3A%2F%2Fwww.buckhornyachtharbour.com%2F&ei=HTNaVff-EIGXyATXvIDAAg&usg=AFQjCNEsq8k-6mp6zpQntR3tP6J5Pw_xCQ

Edited May 18, 2015 by lew

[davey buoy]

The hub can be rebuilt.Had it happen on my 40hp Evinrude years ago.

[mattybculp]

Thanks Lew and Dave. Should I just take the prop off and take it to them vs trailering the boat out there ?

[davey buoy]

Thanks Lew and Dave. Should I just take the prop off and take it to them vs trailering the boat out there ?

Yes,the prop is all he needs.

Edited May 18, 2015 by davey buoy

[John Bacon]

So if it was a spun prop does that mean replacing the prop or have it rebuilt.?

 

Either option will solve your problem. Rebuilding will be somewhat cheaper; however, a brand new aluminum prop is not usually too expensive. In some cases you can swap your prop for another rebuilt one for the same price as having your own prop rebuilt. That way you do not have to wait.

[OhioFisherman]

Sounds like a spun hub to me also, get it repaired and pick up a spare prop to carry in the boat?

[mattybculp]

Thanks for all the advice folks. Really appreciate your input.

[Rizzo]

Had the same thing before...spun hub. Wasn't too costly a fix

[mattybculp]

Just an update and hopefully some more feedback. So I was certain it was a spun hub however my old man wasn't. We took the prop off and examined the interior hub, and nothing looked alarming. So I put the prop back on and marked a line on the prop and nut etc to see if she is spun. We took her down to Indian river with the old man and sure enough the boat made a liar of me performing perfectly. So we get home I check the lower oil and it looks good. We are out last night on rice trying to out run that storm all the way to bewdley but the weather changed 360 and there was no getting out of it. Well wouldn't you know down at the other end of the lake the motor starts doing the same thing, acting exactly like a spun hub does. The boat will putter along at maybe 10 km but when more throttle is given its like its been thrown in to neutral or something. So my dad says try to putting her in reverse I did that and then the motor returned to running as normal. It did it again later and we did the same thing by putting it in reverse and it worked again. There are no weeds on the prop. I repeat no weeds on the prop. Lol. We get back and trailer the boat up and sure enough the lines we marked to see if the prop spun were in the same alignment, so no spun hub. This motor runs like a top, other than a little squealing in reverse it has never let me down and has always been well maintained, stored inside etc, but this is a head scratcher any thoughts, before I shell out $95/hour to find out. Thanks for all your input. I was really hoping it was a spun hub, but I have to say with confidence I don't believe it is.

[Sinker]

Maybe a clutch dog slipping? That would make it slip out of gear....

 

I use the mechanic in bewdley beside BJ's Bait and Tackle. Good guy, fair price, and he does great work. MD Marine. 905 767 3777. His name is Doug.

 

S.

[Zamboni]

Doesn't sound like a spun hub then....next I would look at the shift cable (best case), see if the adjustment/clamps are secure, not damaged etc....pop of the cover and check the linkage adjustment. Google will show lots of how-to's with pics. If not that it's probably the clutch dog.

[Sinker]

Yes, check the linkage first for sure. Mine came loose on me once before and I lost reverse gear altogether.....quick adjustment and I was back in action.

 

S.

[Steve Piggott]

Check that all cylinders are firing. Might be plug pack.My boat did that a few years back was only running on one cylinder. Would run slow but not full speed.

[mattybculp]

Thanks Shane ,Steve, and Zamboni. I'm going to check the linkage cable. And if not I may be biting the bullet on sending her to the mechanic.

[Lape0019]

Highly doubt it's the clutch dog. They make an aweful racket...

[mattybculp]

It's not making any sound other than the little squeal that happens in reverse from time to time. But nothing noises at all. Whatever is happening when it does "spin out" putting it into reverse seems to correct it for the short term until it eventually " spins out" again. I will have to take it in. It's the only way I can think of describing it.

[Lape0019]

When it spins out, do the RPMS increase or remain constant? I still wouldn't rule out the spun prop if the rpms spike but if it remains constant, there might be something else wrong. It wouldn't hurt to bring it in. There always seems to be something to tinker with and although shop rates can suck, nothing is worse than having a boat that continues to give you issues.

[mattybculp]

The RPM'S increase when it does it.

[Sinker]

It sure seems like a spun hub to me, but you could have something going on in the gearcase too. I'd get another prop and try it first.

 

S.

[Lape0019]

Very Possible.

 

Have you hit anything with it lately? Stump? Shoal?