No speed and hard steering

TickledPink

We managed to get out on our FV 250 today. Spring has arrived 🙂
Doing the maximum 6 knots along the river to Cowes Harbour was fine. The tide was going out and was nicely carrying us.
But (there's always a but), once out in the sea, despite accelerating, I couldn't get the speed above 10 knots and the steering was really hard, continuously trying to steer to starboard so I was fighting to keep it going in a straight line. I tried the trim tabs all the way down, all the way up, and various places between. 
When accelerating, the bow was up high and the swim platform was under the water. The engine noise changed with acceleration, but the speed stayed the same at 10 knots.
What am I doing wrong?

GMSLITHO

Is the drive all the way down 

TickledPink

I held the drive trim down and I could hear the motor working but I couldn't tell if it was right down. Does it stop when it's fully down? 

Grahamu

Motor does not stop running but the sound changes, visually check the drive position with engine off. Check your power steering reservoir for fluid and the belt is tight.

TonyG13

Do you keep the boat in the water or did you launch it from land? If in water and not bottom painted could be growth on the hull?

YYZRC

What were your RPMs at full throttle?

Drive should be all the way down and tabs all the way down when launching for quickest time to plane. 

TickledPink

@TonyG13 the boat stays in the water and is copper coated. It was out of the water in December and completely clean.

TickledPink

@YYZRC I was so caught up with what could be wrong that I didn't check the revs. I'll do that next time!

TickledPink

I manage to get out on the boat again today. I couldn't get faster than 7 to 8 knots. Revs at that speed were 3750 and the throttle was 3 quarters forward. If I pushed it flat out, neither speed or revs increased.
The trim dial showed trim right the whole time.
Pressing the drive trim button up and down, I could hear the motor and could see it affecting the bow up and down so that appears to be working.
Pressing the trim tabs up and down, I couldn't hear a motor and whether the lights on the trim tabs control showed them as right up or right down, it made no difference to the boat performance, so I'm guessing that neither trim tabs work at all.
I'm going to have to get it looked at. 

YYZRC

You should still be able to get on plane without using the trim tabs, but not at 8 knots! 

Did you still have the hard steering issue? Did you check to ensure your power steering fluid level is ok?

Aqua_Aura

3750 RPM and only 8 kts? Maybe your drive is trashed and slipping? 

Ian

Spun hub? Had that on my prior Bayliner and to a point increased RPM did nothing.

aero3113

Ian said:

Spun hub? Had that on my prior Bayliner and to a point increased RPM did nothing.

I had the same on my 242, @TickledPink if you have an alpha 1 drive (not sure if Volvo props have hubs) that can be your issue.The only thing is that in your first post you said your bow was up high and you swim platform was in the water. I don’t think a spun hub would be able to push that hard.

aero3113

I had some line stuck around my prop once on my 242 and it did what you’re experiencing….

TickledPink

Thanks. I'm going to brave getting in the water (it's only 11°C) to check the prop. 
It's a Mercruiser 5L with duo prop stern drive. The pic is from January. Its been in the water all winter.

aero3113

You should be able to lay on the platform and with the drive all the way up feel around the props.

TickledPink

Ahhh ok, thanks @aero3113, I'll do that.

TickledPink

@YYZRC the steering wasn't hard this time. I checked the power steering fluid and it was fine. It was quite choppy last time so maybe that, with the slow speed, was the reason for the hard steering. I don't know.

YYZRC

If it's a Merc engine with two props (Bravo 3) there is no hub to spin. You could have an issue with your coupler, though.

davidbrooks

Double check all your spark plug wires. Make sure they're all seated. I had a poor performance issue on one of my engines and it was all due to one of the spark plug wires being loose.

mattie

davidbrooks said:

Double check all your spark plug wires. Make sure they're all seated. I had a poor performance issue on one of my engines and it was all due to one of the spark plug wires being loose.

@davidbrooks
My vote here as well. Check if the cap/rotor needs to be replaced on distributor. 
Running but - no power is a big indicator.

Aqua_Aura

He appears to be making RPM so this is something outside of the engine such as outdrives prop etc. 

YYZRC

Seems like possibly multiple issues. I agree with checking cap/rotor and plugs/wires as those are easy and free.

With the motor spinning at 3750 rpm and the boat only pushing at 7 knots you are either very low on torque (several cylinders not firing) or your coupler is shot. 

Grahamu

If the engine is running at 3750RPM I doubt it's an engine problem. More likely a drive connection problem or a severely fouled bottom.

rasbury

Your wife isn't under the boat is she?

aero3113

If the coupler was shot, wouldn’t he over rev? Just like if it was a prop hub that went bad?

Aqua_Aura

I think something is binding in the outdrive. Either way this boat needs to get out of the water and looked at. 

YYZRC

I think you are right @aero3113

Pat310

TickledPink said:

The pic is from January. It’s been in the water all winter.

If the boat has been sitting in the water all winter I would guess fouled bottom 

Grahamu

After leaving an anchorage one day I forgot to lower the drives from the half up position and experienced a similar situation, the boat does need to come out of the water to check everything.

TickledPink

Thanks everyone, I'll arrange for it all to be properly looked at.