Sluggish Takeoff

Shabah212 · 06-20-2014, 11:12 PM

Hello all!

First time poster!

I just bought a 1997 Shabah Z212 5.7L Alpha I with a 21 pitch stainless prop. The boat has 345 hours on it. I bought it off my girlfriends parents who had it for about six years (second owners). I had ridden in the boat many times while they were still owners without having this issue. The first time we (just my GF and I, full tank, and 1 cooler) took it out it ran fine. Throttled it to get on plane and the bow never even came up.

The past couple times we have taken it out; however, I have given it throttle and the bow starts to raise then its almost like it just loses all power. It will go bow up for sometimes 15-30 seconds before it breaks over and takes off. Once it is going, say 2500 RPM at about 30 mph, I can hammer on it and it will set me back in my seat and take off. Its just that initial taking off where I am having an issue.

As I stated, I have ridden in the boat many times with 6+ ppl pulling a wake boarder and never had this issue before. It does have a carb, but I am hoping it is something as simple as bad gas. We stored it with a full tank and fuel treatment, but ran most of that out and filled it again with a can of Seafoam to go with it.

I would just like some ideas on where to look or what to do. One concern I may have is that the battery is very old. Just wondering if this could be affecting something when I am taking off, then when I get the RPM up it is not an issue.

Any help is appreciated! Thanks and look forward to learning as much as I can!

***mikeyt*** · 06-21-2014, 12:30 AM

The problem is more likely related to that 21" pitch prop. Its a decent prop for cruising but wont be good for low end grunt. Most likely you will need to buy a 19" 3 blade or a 20" 4 blade to improve the low end stuff. And, while you're at it, i would consider adding a pair of Smart Tabs to improve getting & staying onto plane. Do a site search for Smart Tabs and you will find a number of threads discussing their benefits & their ease of installation or you can read about them here at the Nauticus site.

Also, just for some self education about props, take a few minutes to scan thru the STICKYS at the top of the Prop Talk Forum.

Shabah212 · 06-21-2014, 08:00 PM

I had considered it being the prop; however, since it has only recently started doing this I decided that was not my whole issue. It the past it has ran fine with 6+ people and pulling a wakeboarder - that was really why I decided this was not the issue. When my girlfriends parents owned the boat, her dad took off a 19 pitch stainless and went to the 21 for more top end, he said there was only a slight difference in bottom end. He said it has never taken off as sluggish as it does now.

Thanks for the reply!

***mikeyt*** · 06-22-2014, 04:05 AM

Hmmmm... might be worth changing the fuel filter but does your father in law still have the old 19" prop? It might be worth giving it a try to eliminate any prop issues.

***ShabahZ280*** · 06-24-2014, 08:54 PM

Change the fuel filter. That'd be my first recommendation on where to start. Then get as much new fresh gas in there. If you can get 89 octane with no ethanol (marine gas), that'd be the best. Start there, and then look into if your engine has the "cool fuel" system on it, and/or start checking out the fuel pump.

MikeyT may be right about the prop too. Doubt it'd have anything to do with the battery.