Damaged Prop?

[shanklejo]

Can a damaged prop keep the engine from running at high speed? Can it cause a rough idle? Can it make the engine hard to crank? I have all of these problems, as well as, a damaged prop.

 

[rickdb1boat]

Re: Damaged Prop?

Yes, a damaged prop can keep the motor from reaching full RPMs. And yes, the prop can cause vibration when in gear at idle speeds(But not when in neutral). It will not make the engine hard to crank, though. Sounds as though you have other issues to deal with, too. Post some more info and maybe get some further help. A little history of the motor will help...

 

[shanklejo]

Re: Damaged Prop?

I'm embarrased to tell you more about the engine, but I will. The boat is a 16' deep tri-hull that I bought for family fun, mostly fishing. On our next to last outing, the prop was chipped and knurled some. I was still able to run it in high speed but performance was not as good. I let it set for about a year and had the water pump replaced. Took it out and experienced the performance that I described in the first thread. The prop had been amatuerishly repaired. The engine is a 1974 85HP Johnson.

 

[tashasdaddy]

Re: Damaged Prop?

first don't run it with damaged prop, the vibration will take out the lower unit in a hurry. after sitting for a year, you probably need a carb cleaning and reassembly with a rebuild kit. this will get rid of all the varnish crud in the carb. flush tje fuel line before reconnecting. these thing don't like to sit the like to be run more often. it's also time to do a decarb with Seafoam Deep Creep also don't attemot to start it with out haveing a water supply like muffs, or you will be buying a new impeller again.

 

[shanklejo]

Re: Damaged Prop?

Already got the rebuild kit and in process of doing it. I have water muffs. Seafoam Deep Creep is new to me. Is that an additive or a spray cleaner?

 

[rickdb1boat]

Re: Damaged Prop?

Seafoam is an additive and decarb agent that is added to the fuel. Deep creep is a spray decarb product that is sprayed directly into the carbs/cylinders for remove carbon deposits. Both are available at NAPA auto parts. Normally in the FAQ section of this forum, there are a couple of good articles about decarb. But they are down for maintenence right now. Check it later on for more info...

 

[shanklejo]

Re: Damaged Prop?

Thanks for all the info. I expect to be putting my boat up for sale when I get all this stuff taken care of. Oh, and I'll do a gel-coat restoration as well. This boat is sooooo difficult to fish from. You better sing out when you lean over the side or your fishin buddy will be in the water.

 

[tashasdaddy]

Re: Damaged Prop?

there is a post right now with a link to the decarb directions for seafoam "decarb directions"

 

[shanklejo]

Re: Damaged Prop?

Boy there sure was a lot of info about the decarb procedures. Old Tom has figured out the easy way to do it. Don't do it at all. My repair manual says to never add anything to the gas except motor oil. Wouldn't they (motor manufacturer) know what's best, or are they hoping I'll need a tune up and I can pay them to do this. That's how the automobile manufacturers operate. I've always had the impression that boat people were different. That they really had your best interests in mind. Maybe not, anymore, huh? I'm still not convinced that the stuff won't harm rubber seals, let alone engine parts. Where can I find a motor magician who can prove this?

 

[wilde1j]

Re: Damaged Prop?

The engine manufacturers sell decarb products (BRP 'Engine Tune', etc.). All 2 stroke motors can benefit from it once in a while. The NAPA proiduct (Deep Creep) is easier for some to find and is the same stuff.