1994 Force 50 on Bayliner Capri 1401LS Slow to Plane

[daboostcreep]

I was given a very very good condition 1994 Bayliner 1401LS with a Force 50 motor.

The motor starts up immediately and runs smooth.

The problem is the boat doesn't hole-shot very well and requires quite a bit of time to get on a plane, with just myself on the boat at 190lbs, and once on a plane it runs at about 22 mph indicated.

If I add another adult of about the same weight at 180lbs it becomes a slug and doesn't want to plane out, basically making the boat useless.

I know this much:
Compression is 120 psi per cylinder
Jets are clean and carburetor is otherwise clean.
Prop was replaced about 10 years ago with a 10 degree pitch Quicksilver unit.
Fuel is run at 50:1 mix and plugs are new.

I don't know this:
Factory prop pitch, or recommended pitch to get on a plane quickly.
RPM at WOT as I didn't have a tachometer with me.

Thoughts:
Maybe the timing isn't set aggressively enough?
Maybe the prop should be different pitch?

I appreciate your help in advance.

 

[SkiDad]

For whatever reason, they used a really high gear ratio on the earlier Force 50 engines - 1.62:1 - Most engines in that size would have a 2.00 or a 2.30 ratio lower unit. So you have to go lower pitch on the prop to accommodate.

at 10p you are probably turning around 4500 rpm and that is below your range of 4750-5250, and I would suggest going down in pitch. I would be temped to go down to 8 b/c of the slow holeshot you mentioned. That should put you closer to 5000 rpm - you might loose 2 mph with all of these changes but I don't think you have a lot of choice. I'm making a few assumptions here so if you pick up some kind of tach for the boat that will help you dial it in better, even if it's just an induction tach like the Tiny Tach knock offs. You could also check the actual speed with a GPS app on your phone.

one other thing you could do first is weigh your setup at a truck stop - that thing should be around 1500 lbs with trailer. If it weighs something like 2000 lbs you may have water logged foam.

PS - i'm just now adding this - looks like 10p might be the smallest prop for you engine - so i wonder if you have other issues ?

 

[jerryjerry05]

You do a spark check?
​These 50s can run good on 1 cy.

 

[daboostcreep]

Thanks for the responses guys.
The boat is stored 175 miles away, so the next time I'll be up there is in about 3 weeks.
So for the time being I'm collecting ideas and things to check.
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Things I will do in order:

-There is a drain plug at bottom center of the hull which I will remove while on trailer to check for water in hull (I doubt it as the boat has been stored indoors for the last 13 years, but anything is possible.)

-I have a tiny tach that I plan to attach to check for max RPM.

-I will check speed at WOT with just myself in the boat with cell phone GPS.

-I will bring a spark tester to check both plugs for proper spark, but based on both plugs coming out identical when changed, I assume the spark is good.

-I discovered the flywheel, stator and other ignition components were replaced by a shop before being stored 13 years ago, which makes me wonder if the lack of get up an go could be that the timing isn't correct and enough advance isn't set properly??? Fresh plugs have a dark black carbon buildup after being run for an hour, possibly due to not enough advance??

 

[jerryjerry05]

The air screw could get the carbon on the plugs.
Start at 1 and 1/2 turn out.
Turn it in slowly, count the turns and post them.

 

[Chadomosis]

What's the condition of your prop? I sharpened mind up and cleaned of all the dings and stuff and it made a huge difference on how well it gets up and goes on the water.

 

[djsforce]

I have the exact same combination, and when I bought it several years ago, had the same issues as you when it first came out of a long storage period. Over the years I did a few things that helped. The inboard fuel tank is huge and sits at the back of the boat. I switched to a portable 5 gal tank and saw some improvement. If it's a manual tilt, place the pin in the second to last set of holes (towards the back) to lift the front up a bit (and it will increase your rpm). The floor on mine had started to rot and hold water, I saw some improvement when I replaced the floor. I also tried a hydrofoil and it reduced my top speed and didn't appear to help get on plane any faster, so I removed it. A few years ago I replaced my lower unit with one that spun easier than the original. It brought my revs up to about 5700 with a 13 1/2 prop and it's now the fastest it's ever been, running 30 mph with one person. My teenage son says he's hit 32 mph with it. Good luck with your boat!

 

[daboostcreep]

I'm back a year and a half later...I just finally got back in the water.

I did a seafoam shock treatment on the boat with 3/4 gal of 87 octane, 3 oz of oil and 1 can of seafoam pulled directly into the carb, bypassing the fuel tank. I then put 5 gallons of fresh fuel and oil mix into the tank with another can of seafoam and ran the boat. The motor starts immediately and runs very smooth.

Myself (190lb) and uncle (240lb) were able to record 4750rpm and by myself I got up to 4850.
With the two of us in the boat its slow to accelerate and get on a plane. By myself its better, but not great.
This is with the 10 degree prop.

Next time up there, hopefully in a few weeks, I'm going to check the timing.

Until then, based on this information regarding RPM's etc, would anyone knowledgeable recommend a prop change? 13 degree prop? Part #? Anything else? Does it need 91 octane?

 

[jbuote]

Nowhere near a pro here, but I think I might get the boat weighed as suggested earlier...
Pulling the plug at the back, won't drain water if it's in the flotation foam etc..

I know you said it was garage stored for 13 years, but if the water was already in there, I don't think it went anywhere..
If the boat is heavier than it should be, then the foam is probably filled with water...
Even 500lbs heavier is the same as adding 2-3 people to the boat, so when you're alone, you really have 3-4 people on board.
You and your uncle, plus sogged foam is like 4-5 people on board.. etc....

Others can/will guide better, but that's probably where I'd start since RPM seems close to proper range, and you say it runs smooth...

Hope it helps...

 

[jerryjerry05]

Had a Bayliner 15ft. with a 50hp.
Was redoing the deck, the foam wasn't that thick that it would hold 500# of water.
Maybe 50/60 at the most.
Cut up a Bayliner 21ft. center console, the foam in that was a BUNCH and it held a lot of water.
But nowhere near 500# Maybe 100# or more??

If the rpm's with just you in the boat are 4800 I'd think about dropping 1 pitch.
What things are with you when you go?
Coolers, toys, gear, etc. ???
One person, life jackets and 6 gal gas and safety equipment.
Then go for a ride.

Michigan Propeller has a prop finder service,
Contact them and give them the info and they can recommend the right size.

 

[daboostcreep]

I'm running a 10 degree prop already, which I believe is the lowest I can go?
If I could find an 8 or 9 I'd probably buy it if the price is decent.

I had nothing in the boat at all, just myself, with a full tank of fuel.

I'm mostly concerned with acceleration. The back squats, the nose picks up and its slow to increase in RPM from 3000-4500. I assume its due to the lack of it's ability to get on a plane so the back is pushing lots of water which the little 50 doesn't power through very easily. Top speed indicated on speedo was 26mph.

I'm starting to wonder if Smart Tabs would work to help get the nose down after punching the throttle so the resistance in the water is less at lower RPM. Doesn't solve my max RPM issue, but may help with overall performance?

 

[kbh121956]

Do you have tilt and trim on it? if not I have found that the pin needs too be in the second hole out from the transom.

 

[daboostcreep]

I have the tilt of the motor on the second hole from the transom.

I've been searching around on the internet and i'm finding ideas like moving the motor up higher on the transom to reduce drag. I saw the recommendation to have the fin that's above the prop be 1-2" above the bottom of the hull.

I really want this little boat to work. Spending a bit of cash to raise it on the transom and or smart tabs is something I can handle if the results are as expected.

 

[kbh121956]

Post a photo with the motor down so that we can see where it sit's with the bottom of the transom.

 

[jerryjerry05]

Usually the motors installed correctly.
You do a compression/spark tests?

 

[daboostcreep]

Usually the motors installed correctly.
You do a compression/spark tests?

compression was 120 psi last time I checked and I think to reach 4850 RPM the spark must be good.

 

[jerryjerry05]

Compression can change from 1 trip to the next.
Maybe the tach is wrong?

When it's accelerating, does it rev up and not move? Prop hub.

 

[daboostcreep]

Compression can change from 1 trip to the next.
Maybe the tach is wrong?

When it's accelerating, does it rev up and not move? Prop hub.

The compression test that I ran was prior to my first time getting the boat in the water for the first time in over 10 years.
The slow to accelerate and plane condition was present when I put it in the water that first time.

The motor simply increases RPM slowly and as a result, its slow to plane.
If the RPM jumped like crazy I would think the hub on the prop slipped or extreme cavitation etc.

 

[jerryjerry05]

Do a spark check?
These 50's can run on 1 cyl.

Is the timer base advancing as you accelerate?
Is the exhaust snout still in place?