Jump to content
Strawberry Orange Banana Lime Leaf Slate Sky Blueberry Grape Watermelon Chocolate Marble
Strawberry Orange Banana Lime Leaf Slate Sky Blueberry Grape Watermelon Chocolate Marble

Featured Posts

32 minutes ago, Wrinkley said:

Understand what you are suggesting but if two separate systems to measure revs that I'm using are roughly in line why would a third be different? 

 

I wasn't aware you had two separate means of measuring revs until now. What are these means?

Share this post


Link to post
Share on other sites

Both belts run from the engine pulley to the alternator pulley, they run in parallel. The cycle rev counter sensor is mounted on the inside of the engine pulley. The frequency counter is used on the one phase of the alternator stator winding. The engine to alternator pulley ratio is 3:1.

Share this post


Link to post
Share on other sites

Thanks for the link. For a tenner it's got to be worth it. Just as an aside, how do you know the new one is accurate and your original one faulty?  😇

Share this post


Link to post
Share on other sites
36 minutes ago, Wrinkley said:

Thanks for the link. For a tenner it's got to be worth it. Just as an aside, how do you know the new one is accurate and your original one faulty?  😇

Try pointing it an mains powered led light it may just measure the mains frequency

Share this post


Link to post
Share on other sites
3 minutes ago, ditchcrawler said:

Try pointing it an mains powered led light it may just measure the mains frequency

Or a conventional fluorescent lamp.

 

It should flicker at 100Hz so show as 6,000rpm.

Share this post


Link to post
Share on other sites
3 hours ago, Wrinkley said:

On full throttle there is still fuel running back to the tank indicating, to me, plenty of fuel available to the pump.

 

Is that really right?

 

The leak-off pipes should barely carry anything as I understand it. On my Kelvin I only get about half a litre in several hundred hours accumulating in the scotch bottle.   

Share this post


Link to post
Share on other sites

No, not from the leak off pipes the over fill pipe from the top of the secondary fuel filter. This, apparently, is to ensure adequate fuel available to the injector pump. 

Share this post


Link to post
Share on other sites
22 minutes ago, Mike the Boilerman said:

 

Is that really right?

 

The leak-off pipes should barely carry anything as I understand it. On my Kelvin I only get about half a litre in several hundred hours accumulating in the scotch bottle.   

It depends on the injection system, on our D3 there is a very significant flow and this comes from both the injection pump and the injectors, I have read that the flow through through the injectors in intended to provide some injector cooling.

 

Many years ago whilst getting the tank sucked out and refilled we attemped a very short cruise (boatyard to nearest VM) running on a 10 litre Jerry can as a makeshift fuel tank. The return still went to the main tank and after about 13 minutes the jerry can was empty

 

................Dave

Share this post


Link to post
Share on other sites

I have a Russell Newbery DM2 in my boat which is 18HP at 1200 RPM. I too have a 22 x 22 inch prop and a 2-1 reduction. It runs fine and clean, reving well. I would imagine that the OPs set up is more or less similar and should run OK. This was the prop that crowthers recommended and made for the boat when it was new. It was said that this would load the engine enough without over propping.

Edited by captain birdseye

Share this post


Link to post
Share on other sites
13 minutes ago, captain birdseye said:

I have a Russell Newbery DM2 in my boat which is 18HP at 1200 RPM. I too have a 22 x 22 inch prop and a 2-1 reduction. It runs fine and clean, reving well. I would imagine that the OPs set up is more or less similar and should run OK. This was the prop that crowthers recommended and made for the boat when it was new. It was said that this would load the engine enough without over propping.

Can you get right up to 1200 rpm on good deep water?

 

...............Dave

Share this post


Link to post
Share on other sites
2 hours ago, Wrinkley said:

Oooo that's a good idea. But then I'm not on mains at the moment. Could measure the hz of my mastervolt. 

You could, mine was spot on when I ran a synchronous timer for a week

1 hour ago, dmr said:

 

Many years ago whilst getting the tank sucked out and refilled we attemped a very short cruise (boatyard to nearest VM) running on a 10 litre Jerry can as a makeshift fuel tank. The return still went to the main tank and after about 13 minutes the jerry can was empty

 

................Dave

I keep the day dank for my Dickinson stove topped up with the return from the filters/injectors. Caught me out with 10 days in drydock last October

Share this post


Link to post
Share on other sites
22 minutes ago, captain birdseye said:

Never consciously tried, I'm not one to 'red line' engines but it revs OK and pushes me up the Trent and motors well on every waterway I've been on. 

Red Line is a rather dramatic term for getting a slow revver up to 1200, thats slower than the tickover of some petrol racing engines 😀.

 

I've had mine running pretty much flat out a few times, once tied up in a lock. I wanted to know that the engine and cooling system were happy at those conditions and thought Id rather find out in a controlled test than in a real emergency. However we have the humble JD3 that revs to about 1300 whilst the base John Deere engine is good to at least 2400 so I knew there was little chance of breaking anything.

 

................Dave 

Share this post


Link to post
Share on other sites

whatever the maximum design speed is for an engine, that is the red line. For instance, my car red lines at 10000 RPM and my motorbike at 6500 RPM. I would run the car up to 6500 easily and be happy thrashing it up to 9000, but if I ran the bike all the time at 6500 I would soon wreck the engine, so for the same reason I wouldn't run an engine with a maximum design speed of 1200 RPM at that speed.

Share this post


Link to post
Share on other sites
4 hours ago, ditchcrawler said:

Try pointing it an mains powered led light it may just measure the mains frequency

If you’ve got a smart phone you can download a strobe light and use that against a mark on a pulley.  If you have a iPhone try “strobe light tachometer” app

Edited by Robbo

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.