Frequency of Impeller Replacement

[myanni74]

I am brand new to boating and just picked up a 1974 Chrsyler 45hp force motor. The compression on both cylinders is 125, so I know the motor is fine there. I wanted to perform some maintence on the motor before I take it out on it's maiden voyage. A freind had suggested that I replace the impeller, check the anode (because I want to use it in both fresh and salt water), and the lower gear oil.

Any suggestions on how frequently I need to replace the impeller and what other maintence items I might need to do to reduce my risks?

 

[bowman316]

Re: Frequency of Impeller Replacement

impellers usually only last 3 or so seasons, But If the engine is pissing water fine, then no need to change. I would change it if not much water was comming out.

 

[myanni74]

Re: Frequency of Impeller Replacement

Thank you Bowman. What happens if it stops spitting water? Is there a risk that I might overheat the motor?

 

[bowman316]

Re: Frequency of Impeller Replacement

Yes, if there is no water comming out, that means there is no new water comming in, and the water will get hot, and the engine could over heat.

The water runs on the outside of the cylinder walls to cool them off.

 

[Backcountry]

Re: Frequency of Impeller Replacement

Should be a pretty strong spit coming out. You may want to add a tell tale, or better yet a water pressure gauge. There is a link at the top of the page that discusses it.

 

[myanni74]

Re: Frequency of Impeller Replacement

Bowman and Backcountry... Thank you for the advice. I think in order to reduce my risk of overheating, I am going to just replace the impeller. I bought the Seloc manual for this motor, so hopefully it is not an overwhelming task and I don't break anything...

 

[bowman316]

Re: Frequency of Impeller Replacement

Just so you don't worry too much, There should be an overheating alarm that sounds when the engine gets too hot.

A really loud siren.

You can test that it works, by touching a piece of metal to a small hole near the key hole, with they key turned to the on position, but without the motor running.

This should sound the horn, when the metal touches.

 

[Frank Acampora]

Re: Frequency of Impeller Replacement

You may have trouble finding an impeller for your 1974. If so go to the Chrysler Crew and contact franzmarine@aol.com. If your 45 is long shaft and if it has the 5 inch leg extension, remove only the bottom bolts. The top ones only hold the insert to the midleg.

On that engine, you must remove the rear shrouds and disconnect the shift linkage at the hex coupler to drop the lower unit.

When I buy an engine for use, not for parts, It is an unknown engine to me with no history. Therefore, I assume that all wearable items are worn and need to be replaced. Thus: I immediately replace impeller, fuel pump diaphragm, and lower unit oil.

Once I have history on the engine, I will change impellers every two seasons or so. I may go to three on some boats, but I cruise my cuddy and a new impeller on that engine is a guarantee that it will not overheat while I am far from the launch ramp. I also carry an extra in the boat.

 

[azlakes]

Re: Frequency of Impeller Replacement

I may go to three on some boats, but I cruise my cuddy and a new impeller on that engine is a guarantee that it will not overheat while I am far from the launch ramp. I also carry an extra in the boat.

... and Frank i bet you could change that impeller while floating out at sea!

 

[myanni74]

Re: Frequency of Impeller Replacement

Frank,

Thank you for the advice. I was able to get the impeller part number for that motor through West Marine. I was able to order it from Mass Marine on Ebay, But I am definetly going to take down that email address because I am sure I am going to need it.

I am going to pick up the lower unit oil this weekend and hopefully get the job done without to much issue.

In your estimation, how long do you think that repair would take by a novice?

 

[jkust]

Re: Frequency of Impeller Replacement

I like this topic. I am leery that my 2003 Mercruiser 4.3 I/O with 50 or so hours should get a new impeller for fear of damage while our 1984 Force 85 HP that we bought new has never had an impeller change or any other maintenance what so ever. I think sometimes this board makes me paranoid. It never even crosses my mind that the Force will ever need maintenance. I am a big fan of 2 stroke outboards but not their fuel consumption or smoke.

 

[RRitt]

Re: Frequency of Impeller Replacement

for whatever it's worth. I did new impeller and new gearcase seals every spring. Partly because i ran into a lot of sandbars, partly because I did it myself and could do both engines in one afternoon, partly because i bought seals in bulk and had enough to do 100 engines, partly because i wanted to avoid expensive repairs, but mostly because i was 100% saltwater and a bolt turned every year is a bolt that doesn't need to be drilled out ... and i would rather do one easy impeller every year than drill out one stainless bolt every three years.