Rinker 2008 350 Getting on plane

mfritz

I have two 350 Max MPI engines and it seems like it is very hard getting the boat on plane. I have the trim tabs all the way down when I take off. Any suggestions? 

Dream_Inn

Could your bottom be dirty?  Most boats this time of year can need a little bottom cleaning if not used all the time.  It doesn't take much to cause this type of issue.

mfritz

Yes the bottom is clean and I have Bravo 3 out drives. The boat is 15,550 lbs plus gas (250 gallons), holding tank and fresh water tank. I only had the boat for around a month but been boating all my life.   

Dream_Inn

I have a friend on my dock with same boat.  It does seem to struggle a bit as well.  It's a large boat for small blocks.  Even the 342s struggle a bit with same motors.  Maybe shift weight to the bow as much as you can?  Does it run ok once on plane?  What is the typical cruise speed at, say 3800 rpm (or wherever you are on plane)?

mfritz

The speed does not work so I am not sure. 

aero3113

@mfritz , if you have a smartphone, download a speedometer app. It works off of the GPS on your phone. Or even better, download the Navionics app and you will get charts to use along with speed.

JimGuy341

Hill Marine 4x4 props.  20p.   

I had the same set up as you.  Twin 350 mpi w/ B3 3x3 props.  Switched to Hill this season.  Money well spent.

YYZRC

Sucked to spend the $2500 but props solved it for me. I had the same issue with my 330. 

LaRea

As an experienced boater, you've checked the obvious stuff, so we're looking for the unusual.  Have a look at your plug wires.  Check for disconnected wires, or chafing that has worn through the casing.  

212rowboat

Cheaper than propsets? Heheheheheeee- strap a NOS bottle and feed your intake with a squirt at WOT right when it starts to bog... hold on. 

skennelly

@212rowboat - that would be awesome

skennelly

https://www.offshoreonly.com/forums/do-yourself-boating-budget/221336-nitrous-oxide-boat.html

Liberty44140

Definitely check the usual things; growth on the bottom, updated plugs, wires, cap & rotor, and fuel filters. My 2006 342 with 350 MPI's had zero issues getting on plane with 6 adults but the 08 350 does weigh 1300 lbs more. If all of these things check out, I'd recommend getting a compression check before investing in the prop's. People on my dock have a Larson 33 with twin 5.0's. Started having issues getting on plane two seasons ago. Finally did the stuff noted above, no improvement. I started telling them to get the Hill 4x4 props but first the local mechanic said let me do a compression check. Zero compression in the #5 cylinder on the port engine. 

MarkB

How do you have the engines trimmed when you start from stand still?

mfritz

Engines are trim down and trim taps are down. Thanks

MarkB

I'd say you have to much weight in the back (that maybe you can consider moving up), and props for better hole shot will fix your issue.

Michael T

The boat is grossly underpowered with 350 magnums even if they are in excellent shape and all else well. It is even significantly underpowered with 377 Magnums. I have posted on this exact topic before and said, at the time the following: I had friends with both boats. The 377s were just slightly better. The 350 magnums were miserable. That boat should never have left the factory with either engine. Minimum 496s better yet 502 magnums for a 350/360/370. There was nothing either one of them could do ( they tried weight shifting, partial gas fills - it was just like shuffling the deck chairs on the Titanic - a waste of time. It was painful to watch and more painful to be on the boat and hear - particularly those 350 magnums scream - trying to wrestle that boat onto plane then rev high to go anywhere, all the while sucking huge amounts of gas. I am sorry to be so brutal but do what both of my friends did (eventually) and sell the boat. It is a lake queen NOT an express cruiser - there is no express in that configuration and never will be. Only someone who respects you as a fellow boater will tell you this. I am truly sorry and wish you had checked threads on here regarding this topic posted, before buying.

mfritz

Thanks for your comments. 

YYZRC

I am sure what @Michael T is saying is accurate as I feel the 330/340 is at the limit with the 350 MAGs.  But all is not lost, as the props will really help - try them first before you give up hope.

Michael T

@YYZRC I agree that new props could improve - somewhat - the performance of this size boat (remember I owned a 2013 EC 310 with twin 350 mags B III and a 2014 EC 360 with twin 502s and B III). My suggestion to @mfritz was not in any meant to be mean. The boat market is presently VERY hot. If mfritz could sell his 350 now and wait until the market returns to normal (likely in 2021 when C19 settles) he could look at 350/360 400 series with 496/502 and have an express cruiser that accelerated in express fashion and was much better on gas. I just don't want to see mfritz put any more money into this situation. Just my 2 cents.

YYZRC

Michael T said:
If mfritz could sell his 350 now and wait until the market returns to normal (likely in 2021 when C19 settles) he could look at 350/360 400 series with 496/502 and have an express cruiser that accelerated in express fashion and was much better on gas.

I looked at 350s when I bought my 330 and they all had 350 MAG or the Volvo equivalent. The price jump to a 360 with big engines as you describe is significant. 

The 350 with 350 MAG will never be a rocket ship but I believe it would be adequate with new props. @mfritz what was your experience when you sea trial’d the boat? Perhaps it is a bottom growth issue more than anything?

aero3113

I know I’ve said it before but my ‘08 330 with 350 Mags and 4x4 props has no issues at all getting up and out of the water. With all configurations of loads. Very happy with the performance. 5000 RPM at WOT @ close to 41 MPH. 3700-4000 RPM cruise @ 28-30 MPH.

mfritz

38 mph at sea trail. The boat planes out but takes a while. When the boat is full of gas 250 gallons and water tank is full I see a big difference in performance. Maybe new props would help. Only have 140 hours on the engines and the previous owner put custom canvas, sea deck and JB stereo. The boat is very nice. At the dock everyone that sees it thinks its brand new.
All comments are welcome. I do not take offence in any comments. Had several smaller boast since I was 16. Now that I am 60 wanted a boat to sleep on at the lake.    

Dream_Inn

I really do think props would make a world of difference, especially if you are mainly having issues with time to get on plane.  I have 496's in my boat that weighs 22k lbs dry & more than 25k wet.  I was able to top 45mph, but took like 12 sec to get on plane.  New props, 6 sec on plane, still get 43 mph (maybe more since my thick bottom paint is wearing down a little).

I like your attitude and I think the boat is a great boat!  I used to have a 310 (2002) Rinker with the 5.0 MPI.  Never an issue getting on plane with that boat, even though people would tell me it was underpowered.

Willhound

And although not cheap, new props are the least expensive way to try and improve the situation. And although I agree that manufacturers sometimes only put in barely adequate power to keep costs down, buyers are to blame to a certain extent also because they want the bigger boat but aren't willing (or can't) pry their wallets open far enough for the engine upgrade. And not everyone is a serious enough boater to notice the difference anyway or maybe aren't experienced enough. How many large boats do you see that are dock queens? They hardly ever leave the slip and when they do it's a short run at low speed to impress the visitors and then back to the dock for cocktails. Just a thought. 

aero3113

@Willhound , we usually anchor in an area near a marina with some big boats. I often say to my wife that we never see any of them move. If we do, they pull out and we see them back in an hour or so. The growth on the bottoms of them must be out of control!

mfritz

I am out in the water every weekend and tie up in a cove or anchor before dark. I guess I like to burn lots of gas. I am at Lake Cumberland in Kentucky.  

Willhound

mfritz said:

I am out in the water every weekend and tie up in a cove or anchor before dark. I guess I like to burn lots of gas. I am at Lake Cumberland in Kentucky.  

Which totally explains why you're asking about getting the boat to run better. Most of the active members here are serious boaters. But I'd hazzard a guess that we 're a minority. Your best options are probably still re-prop and move as much weight forward as you can. Maybe investigate a longer chain on your anchor rode also. It's amazing what 100 feet of chain up in the nose will do for getting on plane. And you will sleep better at night when you anchor out also.

YYZRC

Willhound said:

Maybe investigate a longer chain on your anchor rode also. It's amazing what 100 feet of chain up in the nose will do for getting on plane. And you will sleep better at night when you anchor out also.

I really want to add chain but I don't want to fuss with my rode as it's fine.  What's the best way to go about this?  Do I get one of those add-a-links?

Willhound

YYZRC said:

Willhound said:

Maybe investigate a longer chain on your anchor rode also. It's amazing what 100 feet of chain up in the nose will do for getting on plane. And you will sleep better at night when you anchor out also.

I really want to add chain but I don't want to fuss with my rode as it's fine.  What's the best way to go about this?  Do I get one of those add-a-links?

Don't know if that'll feed through the windlass. My braided rode was frayed so when I changed it I bought one with 50 feet of chain and 150 feet of braid. 90% of the time I'm on the chain. Would have gone all chain but wallet not big enough. Was about $420 CDN delivered to my door from Poco Marine in Vancouver.

cme4brain

mfritz said:

38 mph at sea trail. The boat planes out but takes a while. When the boat is full of gas 250 gallons and water tank is full I see a big difference in performance. Maybe new props would help. Only have 140 hours on the engines and the previous owner put custom canvas, sea deck and JB stereo. The boat is very nice. At the dock everyone that sees it thinks its brand new.
All comments are welcome. I do not take offence in any comments. Had several smaller boast since I was 16. Now that I am 60 wanted a boat to sleep on at the lake.    

new to the forum, new to me this summer 2007 350 with MerCruiser 350, B2 drives, factory 3-bladed prop.  It takes forever to get on plane but at 4100 rpm or so I am 30mph, and WOT with proper trim I am at 36mph.