1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

[NeedaBiggerBoat]

This was like this ever since I bought the boat I only had 4 outings with it so far and its always been like this.

Wide Open Throttle 3200 RPMs should be like 4400 - 4600 32ish MPH

I checked the anti siphon valve and can blow through it clearly one way and not the other just like its supposed to go.

I checked the filter in the carburetor it is paper and that looked good as well.

The carburetor butterflies at full throttle are completely open choke is operating correctly.

I originally thought the prop was the problem but in doing some research the prop that I have on there is actually a little smaller than what is recommended.

When I am filling it with gas the vent on the outside of the boat actually pushes air out so I beleive that is functioning correctly as well.

Fuel is no more than a week old. oil pressure is at 40 at idle and 50 or so under power.

This motor is clean and supposedly rebuilt starts right up idles fine its kinda slow outta the hole but gets on plain in about 25-30 seconds with 4 people and 44 gallons of fuel. The fuel pump is mechanical.
What shall I look at next?

 

[Kainon]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

cant really suggest you do this, but I had a similar problem with a boat, and to check the carb, I had someone else drive while I slowly closed the choke butterfly thereby causing it to suck in more fuel, richening the mix and revealing the Primary Metering Spring was WRONG and one of the RODs wasnt the same as the other and this was a BRAND NEW REMAN'd 4bbl Carb !!!

anyway when closing the choke, the power increased dramaticaly.

 

[NeedaBiggerBoat]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

cant really suggest you do this, but I had a similar problem with a boat, and to check the carb, I had someone else drive while I slowly closed the choke butterfly thereby causing it to suck in more fuel, richening the mix and revealing the Primary Metering Spring was WRONG and one of the RODs wasnt the same as the other and this was a BRAND NEW REMAN'd 4bbl Carb !!!

anyway when closing the choke, the power increased dramaticaly.

suggesting I not do that makes me wanna try it even more. If it is only a carb problem and lean condition I will be ecstatic. I'm gonna look at my manual and see if it says anything about adjusting the carb I could also try that while out of water for a baseline and see where it takes me. I have a vacation planned at the end of this month and my primary goal is to get the boat running great when the time comes. Raystown here I come (hopefully)

 

[Kainon]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

the only basic settings are IDLE mixture, <1200-1500 rpm thats where the primary metering circuit kicks in, then depending on what carb you have if its a Weber type or Quadrajet style, or Holley then the seconaries.

the carb I was playing with was I Webber / Edelbrock style ( i think, but not 100% sure )

another way to check for lean is spraying CARB Cleaner into the engine under load, IF its lean, power will/should improve
If not it will BOG down.

I like to set the Base idle mixture, engine warmed up, @ idle, in gear tied to the dock.

 

[HT32BSX115]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

This was like this ever since I bought the boat I only had 4 outings with it so far and its always been like this.

Wide Open Throttle 3200 RPMs should be like 4400 - 4600 32ish MPH

Howdy,

You know, rather than trying just one thing (that is really #10 below) that may or may not solve or identify the problem, I would do all of it step by step.........

AND although it doesn't mention it, ensure that you have a KNOWN, accurate tachometer and are using a KNOWN speed measuring device (I.E. GPS)




Cheers,




Rick

List of possible causes of low WOT (Wide Open Throttle) rpm.

In no particular order

Engine Won't Reach Operating RPM. Check

1. Fuel condition. Type and Octane possibly old fuel
2. Propeller pitch or diameter, damaged blades
3. Restricted fuel pickup tube or anti siphon valve Fuel System Test
4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
5. Marine growth on hull and outdrive
6. Wrong gear ratio in outdrive
7. Restricted carburetor air intake (clogged flame arrestor)
8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
9. Poor cylinder compression Compression Test
10. Carburetor defective, or wrong type.
11. Fuel pump pressure and vacuum
12. Boat overloaded, improperly loaded, or improperly trimmed.
13. Engine Overheating
14. Engine timing and ignition system operation
15. Remote control cables and linkage for proper travel to open throttle plates fully.​

Don S.


Why is there never enough time to do it right the first time,
But always enough time to do it again? ​

I do not reply to PM's (Private Messages) regarding boat/engine problems.
That is what the forums are for.
Only forum/moderator issues will be answered in PM's.
​

​

 

[NeedaBiggerBoat]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

Howdy,

You know, rather than trying just one thing (that is really #10 below) that may or may not solve or identify the problem, I would do all of it step by step.........

AND although it doesn't mention it, ensure that you have a KNOWN, accurate tachometer and are using a KNOWN speed measuring device (I.E. GPS)




Cheers,




Rick

Prop Pitch 19

I have to trim the motor way up to get to 4000 RPM I am using the factory tach and also a shop tach to determine the RPM steady 3200 trimmed up very far I get 4000, I shouldn't have to trim up to get there. The hole shot is really bad especially with the size prop I have on there. Im not so worried about speed i'm just looking to get the engine running right.

the fuel is fresh
checked anti siphon tube and can blow through it one way.
The oil level is where its supposed to be and I have a 40 PSI at idle.
In my situation the marine growth 100% positive thats not it.
Intake is not clogged and clean
exhaust is flowing unrestricted.
the engine is new and i don't have a compression tester.
I think I tested the mechanical fuel pump pressure and it was about 4 or so on my vacuum gauge.
linkages operate normal full carb fully open at WOT.
The carb is a rochester 4BBL

I am at the carb and next will be the ignition system.


The boat bogs down at full throttle from a stop I have to ease the throttle up to get to the 3200 rpm and trim it up rather far to get 4000.

It is something like an adjustment of some sort I am almost positive.

 

[HT32BSX115]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

It is something like an adjustment of some sort I am almost positive.

14. Engine timing and ignition system operation

That's next probably. Retarded timing will absolutely cause inability to make rated WOT RPM everything else being "equal".....

 

[Kainon]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

You may need to trim the boat/drive up more than your comfy with

I trim up till I get the most speed, depending on the boat can be the highest RPM but too much and you'll cavitate the prop, it will slip and you'll lose RPMs. If you have the nose of the boat too far down it pulls the RPMS down on the engine as is harder to push
the boat through the water.

What condition is the prop in ? and what type of prop is it.

 

[NeedaBiggerBoat]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

You may need to trim the boat/drive up more than your comfy with

I trim up till I get the most speed, depending on the boat can be the highest RPM but too much and you'll cavitate the prop, it will slip and you'll lose RPMs. If you have the nose of the boat too far down it pulls the RPMS down on the engine as is harder to push
the boat through the water.

What condition is the prop in ? and what type of prop is it.

Im not sure what brand but I have 2 they are both 14 1\2 19 Pitch one is aluminum and the other is stainless steel.

I was under the impression that trimming up when in deep enough water was not so good on the U Joints but for testing purposes I did it to see. It was trimmed so far up to where it was almost at the point of cavitation. The aluminum prop is like new condition and the SS one has a few nicks with no bends in the pitch.

I will reset the idle and re tune the idle air\fuel mixture screws with a vacuum gauge tomorrow looking to get the 20 PSI manifold vacuum pressure it supposed to get.

 

[HT32BSX115]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

Im not sure what brand but I have 2 they are both 14 1\2 19 Pitch one is aluminum and the other is stainless steel.

I was under the impression that trimming up when in deep enough water was not so good on the U Joints but for testing purposes I did it to see. It was trimmed so far up to where it was almost at the point of cavitation. The aluminum prop is like new condition and the SS one has a few nicks with no bends in the pitch.

I will reset the idle and re tune the idle air\fuel mixture screws with a vacuum gauge tomorrow looking to get the 20 PSI manifold vacuum pressure it supposed to get.

I almost always 'hole-shot' with the drive trimmed down (IN) nearly to the stop.

Once I get going, I trim the drive up/out (every time in small bursts) for maximum speed for the RPM I am operating.

That's why the control is right under your thumb.

You will be able to tell when you have trimmed up too far. Obviously, if you're out to the point of cavitation, you've gone too far!

It's also possible that you're over-propped.

Did it ever make the correct RPM with either of those props? If not, and the engine is running correctly, you might need to go to a 17P prop.

 

[Howard Sterndrive]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

the engine is new and i don't have a compression tester.
I think I tested the mechanical fuel pump pressure and it was about 4 or so on my vacuum gauge.

3 steps I would take in this order:
1. get a compression tester - they're $20 and you are wasting your time troubleshooting an engine with unknown compression. Maybe the valves are misadjusted. Compression test will tell a lot.
2. check block casting number and google it to make sure it's a 350... maybe it's a 283 or a 305 or a 260... can't tell by looking at it. I might do same for the heads. Rebuilders have put 305 heads on 350s before.
3. check fuel pressure running down the lake at wot - testing it at the dock or in the driveway is rather meaningless, and if you read 4 psi, it's probably going to read 1 or zero under full load.


also- clean the flame arrester. not look at it - clean it with brake clean and air dry it... easy to overlook this one
also - check for exhaust leaks or at least try running with hatch open

 

[NeedaBiggerBoat]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

Well an update on what I did so far, figured since i was already there might as well check these things.

I got new spark plugs the ones in it were CR43TS which may have been fine but I opted for the MR43TS, additionally when I was taking one of them out the ceramic broke and I am not sure if I actually caused it to do that or if it was already cracked but it literally fell apart. (when I am talking about the ceramic I am talking about the outside of the plug where the boot attaches not the inside ceramic.) The gap was below .035 so when I installed the new ones I made sure they were .035.

I am in the process of checking the dwell and gap of the points right now as well as checking the timing. I have a compression tester I will check that after I get the points and timing looked at.

Question:
Do I hook up the vacuum gauge to the hose coming off of the fuel pump to check the fuel pressure?


I currently have the vacuum gauge hooked up in the rear of the intake manifold and getting a reading of 18-20 on the gauge. Idle fuel mixture screws are turned out about 2 1\2 turns considering turning them about a 1\2 a turn in to make it 2 turns each. does this sound about right, I know that they mostly control the lower RPM's now but really didn't want to run it too lean.

Question:
How does the distributor advance is it centrifugal with the springs inside?

 

[NeedaBiggerBoat]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

The dwell is supposed to be 29* + or - 2 it was at 23* out of spec by 4* it is now at nominal 29*
I will edit this post when I find out what the timing is set at and include that also, I am waiting on a timing light from a friend so thats on hold until he shows up. When he shows up I will be able to see if its advancing during slight acceleration on the hose. Not exactly sure how this advances.

The idle got smoother and sounds a little better I hope that's just not my imagination. With the spark plug being broken on the outside and the dwell off I am hoping that this will make things better and potentially fix my problem

Idle set at 525 - 550 The book calls for 500 - 600 so I put it at about the middle

I also replaced the fuel\water separator due to this being a new to me boat also.

No exhaust leaks that I could tell, it is a closed loop system with a heat exchanger.

TIMING UPDATE **

the timing was set at 0*! I bumped it up to 8* I think that my problems are all over for now until the next one pops up can't wait to water test it tomorrow readjust the idle and do some more tests and tweaks.

I am beginning to think that the previous owner might not have known what he was doing.

 

[Kainon]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

in the dist are 2 weights with springs, there is a chart in the engine repair manual to show you what the degree of advance and at what RPM,

when adjusting the idle mixture, in gear in water warmed engine. turn in till RPMs drop, turn out till RPMs drop, then divide, then reset your idle speed if needed. then recheck timing.

to test fuel pressure under load you'd need a T fitting can also get a small inline fuel pressure gauge @ AP Store.

 

[NeedaBiggerBoat]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

in the dist are 2 weights with springs, there is a chart in the engine repair manual to show you what the degree of advance and at what RPM,

when adjusting the idle mixture, in gear in water warmed engine. turn in till RPMs drop, turn out till RPMs drop, then divide, then reset your idle speed if needed. then recheck timing.

to test fuel pressure under load you'd need a T fitting can also get a small inline fuel pressure gauge @ AP Store.

Thanks for the insight i will do just that.

I have encountered one other problem as for the severity of this issue i can not say. The dwell reading changes when given throttle which in turn tells me that the distributor shaft has excessive play. Is it bad to run it like that and will a lot of damage occur if this fails?

Thank everyone for the help one day I will be able to help others here as well but I have a feeling that it will take me a little while as I have only begun to scratch the surface of the boating world.

 

[Kainon]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

I'm pretty sure the dwell change WILL change with RPM.. I think that the dwell reading at different RPMs is also specified in the service manual. I'm sure it has to change, I'm sure it does. I've read it does, havent used a dwell meter in a long time though.

 

[bruceb58]

Re: 1989 Four Winns Sundowner 205 5.7 350ci 3200 RPM's at WOT

I'm pretty sure the dwell change WILL change with RPM.. I think that the dwell reading at different RPMs is also specified in the service manual. I'm sure it has to change, I'm sure it does. I've read it does, havent used a dwell meter in a long time though.

Dwell should remain constant at all RPMs. If it doesn't, you have a worn distributor.