Universal Diesel engine no power to prop

[Fox1134]

Ahoy all,

I recently bought a Catalina 30 and have run into an issue.

I am able to start the engine and it sounds/ runs fine. There were some overheating problems but after clearing the water intake of growth I haven’t had that issue since.

The problem I do have is no matter how much throttle I give the engine while it’s in gear, forward or reverse, there is not enough power/ speed for us to move. The prop is spinning as I can see disturbances in the water and we have some motion from prop walk. I have cleaned the prop shaft and jiggled the prop to check the cutlass bearing. All seemed fine. There is still some growth I can’t get off of the prop but nothing huge

Any ideas for what could be causing this problem?

Thanks!

[fox9988]

Sounds like a possible lack of fuel. Fuel filters, tank vent, pickup tube, throttle linkage, etc.

[Fox1134]

Originally Posted by fox9988

Sounds like a possible lack of fuel. Fuel filters, tank vent, pickup tube, throttle linkage, etc.

Gotcha I’ll take a look thanks!

Anything I should check with the transmission?

[fox9988]

Originally Posted by Fox1134

Gotcha I’ll take a look thanks!

Anything I should check with the transmission?

Just that it's full of clean fluid. It's usually recommended to change old, dirty fluid 3 times in a row. Run it in gear for a few minutes between changes.

[gonesail]

how much growth on the prop? make sure you get if off.

[SailingHarmonie]

Lots of advice, but nobody is asking the KEY QUESTION.

What RPM is the engine turning?

If throttling forward has no real increase in RPM then the problem is completely different than if the engine speeds up, but the boat doesn't move.

Also, when you say the boat "doesn't move" do you mean that literally?

[Fox1134]

Originally Posted by SailingHarmonie

Lots of advice, but nobody is asking the KEY QUESTION.

What RPM is the engine turning?

If throttling forward has no real increase in RPM then the problem is completely different than if the engine speeds up, but the boat doesn't move.

Also, when you say the boat "doesn't move" do you mean that literally?

We got the engine turning around 2500 rpm with movement from the prop but not enough speed to steer by or really register as any kind of movement forward or backward

I just checked the transmission fluid and it’s a bit black

Could this also be an issue with the prop shaft coupling at the transmission?

Thank you all!

[skipperpete]

Am I correct in thinking that you have two Catalinas, a 27 (with the Westerbeke) and in the last few months a 30 with a Universal? Does this most recent boat have any history regarding repairs and maintenance in the log book? Last haulout?. Is the previous owner still contactable? Its unusual to lose both ahead and astern at the same time, it could be a buggered drive plate, a prop shaft loose in the coupling or a propeller loose on the shaft but the more logical cause of your problems is the gearbox, either the shift lever adjustment or any of the multiple common internal problems with Hurth gearboxes. Did it by any chance get towed for any distance?

[Searles]

If the prop shaft turns at a reasonable speed but no power ahead or astern ,check that the prop shaft key hasn’t stripped or corroded away,have seen this a couple of times ,interestingly both on Catalina’s with a bronze shaft and a BRASS key .

[boatpoker]

Find gear reduction
Paint mark on the shaft (inside the boat)
Use cheap lazer tachometer to determine shaft RPM
Calculate what shaft RPM should be when engine is at specific RPM.

i.e. If engine RPM is set at 2000 and you have a 2:1 gear box then the
shaft should be turning at 1000RPM.

Do the same on the shaft flange.

This will tell you if the shaft is spinning in the flange or perhaps the gear unit is slipping.

If the shaft is spinning at 1000RPM then either gunk on the prop is worse than you think or the prop is spinning on the shaft.

[massnspace]

Try untying the boat from the dock….…..

[capt jgw]

The damper plate that connects the transmission to the engine is a common failure point. They're supposed to be a consumable part, like the brake pads on a car. You're supposed to replace them periodically but nobody ever does till they break. I just lost one on my twin engine trawler, the shaft would turn slowly and didn't make any thrust. When we pulled the trans off I found I could turn the spline that the trans connects to by hand. The transmission on the Universal only weighs about ten pounds so pulling out is is easy, not so much with my 155lb Velvet Drives. Replacement plate was only about $150, it will likely be less for the little Universal.

[SailingHarmonie]

We are seeing the importance of asking questions BEFORE we jump off on a diagnosis. When there was no information about the engine speed, every single post was about an engine problem. Once we know that the engine is coming up to speed (more or less) suddenly all of the comments are about the drive train.

Other comments now have you looking and answering questions about the actual shaft speed, and that is good, but I am going another way for now...

I know you think the growth on the prop is "nothing huge" but it really doesn't take a huge amount to destroy its efficiency. What kind of prop is this? Probably a 2-blade fixed? Maybe folding or feathering? Can you get a picture of the prop?

[Snore]

Originally Posted by boatpoker

Find gear reduction
Paint mark on the shaft (inside the boat)
Use cheap lazer tachometer to determine shaft RPM
Calculate what shaft RPM should be when engine is at specific RPM.

i.e. If engine RPM is set at 2000 and you have a 2:1 gear box then the
shaft should be turning at 1000RPM.

Do the same on the shaft flange.

This will tell you if the shaft is spinning in the flange or perhaps the gear unit is slipping.

If the shaft is spinning at 1000RPM then either gunk on the prop is worse than you think or the prop is spinning on the shaft.

@Fox1134 do what he said ^^^^^^!!!

One enhancement to that post, if you have an iPhone, there is an app that turns your phone into a strobe tachometer. I used it on my old boat and some deliveries when there were issues. The Android store may have one also.

If the shaft RPMs are right, assuming the prop is the right diameter and pitch, then it is most likely growth.

Finally, you just learned a valuable lesson. Web forums are notorious for folks posting answers that are half-baked.

[NorthCoastJoe]

If the transmission oil is black. Why is it black? I would start there is it slipping?
As said above engine speed vs: prop shaft speed will tell you right away. Don't forget your reduction ratio in the calculation.