Northern Lights Genset impeller change

I bought a new used boat a few months ago. It has a M673 genset and ever manual I down load states to use needle-nose pliers and 2 screwdrivers and pry the impeller out.

The kit has the impeller and pin. I take it that the pin needs to be removed before taking the impeller out. Maybe I am missing something in trying to take it out. I will say that there is only 6" clearance on the front of the genset. So I cannot look directly into the pump housing.

So how do you remove the pin?
Thanks!

No pin on our NL. Just pull the impeller. Careful not to damage the housing.

Cigatoo said:

No pin on our NL. Just pull the impeller. Careful not to damage the housing.

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The impeller, on the inside is smooth. If there is no pin, than how does it work without slipping?

Nope just pull the impeller out the “pin” and all. You will see a hole on your new impeller to thread the new pin through.

The shaft in the pump body has a slot for the pin. I grease my impellers up and you simply compress the vanes and line the pin up with the shaft slot and voila new impeller in place.

I’ve never used the screwdriver method as I’ve read you can bugger the edge of the housing and not get the cover to seal. In tight spots I use angled needle nose, yank on each vane a little and work my way around til it comes out. Some of the impellers come with a little tube of silicon grease.

Iggy said:

The impeller, on the inside is smooth. If there is no pin, than how does it work without slipping?

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Must be different impeller. Sorry for the confusion. Ours takes the standard Johnson. Same as in the Lehman which is convenient.

helm said:

Nope just pull the impeller out the “pin” and all. You will see a hole on your new impeller to thread the new pin through.

The shaft in the pump body has a slot for the pin. I grease my impellers up and you simply compress the vanes and line the pin up with the shaft slot and voila new impeller in place.

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I found a parts book! I can see that the shaft is slotted in the pic. I would rather ask than to break something.

My biggest problem is, there is only 6 to 8" between the belt side of the engine and the bulkhead wall. I am even trying to change the belt and that took me 20min just to get the cover off. But, how do you move the AL to remove the belt. I loosened both bolts, the one in the slotted arm and the lower bolt so it could pivot.

Looking at the parts book, now I am wondering if I didn't loosen the bolt that holds that slotted arm. I can't see it at all. I have used my phone but half the pics are out of focus. Gotta love it!!

It’s very easy to remove the entire pump on that model, makes it a piece of cake to swap out the empeller

Northern Light has a You Tube channel that is growing. Some nice how to videos

Scottbwheeler said:

It’s very easy to remove the entire pump on that model, makes it a piece of cake to swap out the empeller

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Thanks! I just saw a U-Tube on that. Interesting how 2 bolts come out from the other side.

If you’re new to the smaller NLs they give you 3 shots at starting them. That’s it or you run the risk of really screwing them up. A friend told me of his experience not following that rule with the bill that followed so we’ve been completely anal about pulling the impeller and draining it before an attempt at restarting.
On a prior boat the impeller for the engine cooling was real hard to get to. Prior owner had a block of aluminum he drilled out at the size of a compressed impeller. A little bit of household petroleum jelly and your fingers was sufficient to get the impeller in the block. Then it was easy to slip it in the pump housing. Guess the jelly washed away once the pump was run as never had any difficulties.
The bolts that hold the plate on the NL pump housing are minute. We taken to placing a discarded plastic food container under it when removing those tiny bolts. A bit of duct tape to keep it close. Put a scrap of paper towel in the bottom so the bolts don’t bounce. Haven’t lost any but have two spares.
Love the NL gensets. Best I ever had.

3 attempts to start ... then drain the muffler

Scottbwheeler said:

It’s very easy to remove the entire pump on that model, makes it a piece of cake to swap out the empeller

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Had to do that on my old Yanmar sailboat engine. Pump was mounted backwards with the cover facing back under the oil pan. Darn near impossible to get a screwdriver in there and if you did you were working blind. Way easier to just pull the two bolts and remove the whole pump. Gotta think outside box a little. I've got an Onan 7.5 gen in the new trawler, and it needs an impeller. Same access problem so I'll probably do the same, but I haven't yet looked at how to remove the pump. On the hard now so it's a ways down the to do list.

Hippocampus said:

On a prior boat the impeller for the engine cooling was real hard to get to. Prior owner had a block of aluminum he drilled out at the size of a compressed impeller. A little bit of household petroleum jelly and your fingers was sufficient to get the impeller in the block. Then it was easy to slip it in the pump housing. Guess the jelly washed away once the pump was run as never had any difficulties.

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I've done that using hose clamps. The block sounds easier to do but no manufacturing necessary with the clamps. Put two on the impeller and compress, get it started in the hole and remove the first clamp. Push it further and remove the second. Pretty easy. This was on a big fire pump with a 6" diameter impeller. No way to get it in without the clamps.

Great idea!!!

Hippocampus said:

Great idea!!!

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Thanks. I read about that one one of the sailing forums, don't remember which. I've learned a lot on this one too.