Motor won't start when in water but starts fine with muffs

[phabej]

Re: Motor won't start when in water but starts fine with muffs

I had the battery charged all night last night and tried starting the motor again today and no such luck. The motor cranked and raved slower than before. Seemed like it doesn't have enough kick into it. I wonder if I had massed up the timing when I tried manually starting by hand. It didn't sound this bad when I took it to the lake last Sunday. Would that be a possibility? Also I checked all the spark plugs and they all are black. Is that normal?

 

[Mortamie]

Re: Motor won't start when in water but starts fine with muffs

No they are burnt.. U need to get new plugs and double check your oil to fuel ratio.. That could help.. Won't hurt though

 

[phabej]

Re: Motor won't start when in water but starts fine with muffs

Sorry, this may be a dumb question but will any regular spark plugs from Walmart or other retail stores work? Or does it have to be specific type?

 

[Bosunsmate]

Re: Motor won't start when in water but starts fine with muffs

You need the right sized ones, too short and the fire front will start too late.
Too long plugs and the pistons will whack into them. So long as you get the correct sized ones it doesnt matter where you get them from

 

[MH Hawker]

Re: Motor won't start when in water but starts fine with muffs

And the correct heat range, The source wont matter but getting the correct plug sure dose.

 

[Mortamie]

Re: Motor won't start when in water but starts fine with muffs

Take one of your old ones with u to the auto parts shop they will hook u up.

 

[phabej]

Re: Motor won't start when in water but starts fine with muffs

Well, I thought the low compression was due to weak battery so I bought a brand new battery and ran the compression test again but still reading at 50 psi. When I cranked the motor it didn't sound as strong as before anymore. It sounded like it was running on weak battery and doesn't have enough juice. Before when I cranked the motor, it sounded as it was going to fire but just couldn't. Now, it doesn't sound like that anymore. Could any of the following that I did had damaged the motor?

1. Incorrectly mixture of fuel and oil? Not positive but I might have fewer oil in the mixture. Could this have burnt the motor with the 10 minutes that I had the motor ran in the lake last Sunday?

2. When I first did the compression test I was trying to do it by hand pulling the rope instead of electric start, and I think the throttle must not have been lineup fully at neutral because when I pull the rope the prop also spin as the fly wheel spin. Could that have messed up the timing and causing low compression?

3. When I did the compression test using the electric start, I did not ground the spark plug wire that was unplugged. Could this have damaged the ignition?

I think it was getting good compression before because I had no trouble starting it up with muffs. Now it won't even start at all. All four spark plugs were black and I have not replace them. I didn't think it has anything to do with low compression. Would it? Anyway, if it was damaged due to any of the above that I did, could it be fixed or should I just toss it?

 

[bigpoppakdog]

Re: Motor won't start when in water but starts fine with muffs

You can start up a motor on muffs no problem with shot compression. When I was shopping for a new motor this summer this guy showed me how his motor started right up. Did a compression check and one cylinder was a total failure. Didn't even register 1 psi. Battery will not do a thing for compression. Compression reads how much pressure you have between the piston and cylinder wall. It's like trying to such a malt through a straw. If there is a hole in the straw it ain't gonna matter how fast you suck through the straw. There is no timing with a compression test. You are just trying to get the pistons to move a few times to get a reading on the guage. Yes you could damage ignition if you didn't ground sparks plug wires. And one last time, just because she fired right up on muffs doesn't mean anything regarding compression. I could send you the video link of my motor starting right up on the muffs that had two cylinders with low compression. If you are really curious you can remove the cylinder cover and look inside to see the piston and cylinder walls. You could also inspect the head gaskets to see if these are bad. This is just general maintenance advice. Like I mentioned early, not sure the exact specs on your motor.

 

[bigpoppakdog]

Re: Motor won't start when in water but starts fine with muffs

I would agree with the one post regarding psi. I don't believe I've heard of psi readings below 100 on a motor that runs properly. Stop throwing money at it. Fuel/oil mixture, timing, spark plugs, battery have zero effect on compression guage. Rings, cylinder wall, head gasket, piston damage are the things that will effect the compression readings.

 

[phabej]

Re: Motor won't start when in water but starts fine with muffs

Thanks to everyone who responded and gave advice. You guys are the greatest. I will not put anymore time into it and will put it up for sales as parts then. Thanks.

 

[carholme]

Re: Motor won't start when in water but starts fine with muffs

The correct plugs are item 58 under IGNITION DRIVER AND PILOT ASSEMBLY in the parts list above or any equivalent plug from a cross reference chart.

Gerry

 

[Dave1027]

Re: Motor won't start when in water but starts fine with muffs

Thanks to everyone who responded and gave advice. You guys are the greatest. I will not put anymore time into it and will put it up for sales as parts then. Thanks.

The fact that all cylinders measure the same 45 psi probably means there is not a problem with motor compression but the test itself.

You may have a simple problem. I would not junk that motor just yet. Maybe you should take it to a pro and have it diagnosed.

 

[jason011]

Re: Motor won't start when in water but starts fine with muffs

i have the same motor sitting on a stand in my shop, i had it on a boat last year and ran perfect every time i took it out, its compression readings are 83, 83, 80 and 81, your motors compression is way too low, i wouldnt bother wasting money on spark plugs.... if you only have 40 or 45 pounds compression you will never get the ol girl to run right, it needs the cylinders honed and new rings to get your compression back up where it should be ( all parts and labour are going to cost you around $800+ ) i wouldnt bother fixing it, i would buy another motor thats good and keep that as a parts motor, make sure to do a compression test on the motor you buy and if it has under 90 psi on any cylinder leave it where it is because its worn out, also make sure the readings are within 5% of each other, if the readings are all over the place the motor is probably ready to pack er in

 

[bigpoppakdog]

Re: Motor won't start when in water but starts fine with muffs

Yeah the general rule is all the readings should be about 5%-10% the same. But....45 psi is just something that I have never heard of. 80-90 psi from what I've been told from several mechanics is a weak motor. 45.....I would definitely take Dave's advice, call a mechanic or stop in and visit with them. I think most of the smaller shops that work on these older motors will be more than willing to talk to you about what you have already done and answer the psi question.

 

[bigpoppakdog]

Re: Motor won't start when in water but starts fine with muffs

i have the same motor sitting on a stand in my shop, i had it on a boat last year and ran perfect every time i took it out, its compression readings are 83, 83, 80 and 81, your motors compression is way too low, i wouldnt bother wasting money on spark plugs.... if you only have 40 or 45 pounds compression you will never get the ol girl to run right, it needs the cylinders honed and new rings to get your compression back up where it should be ( all parts and labour are going to cost you around $800+ ) i wouldnt bother fixing it, i would buy another motor thats good and keep that as a parts motor, make sure to do a compression test on the motor you buy and if it has under 90 psi on any cylinder leave it where it is because its worn out, also make sure the readings are within 5% of each other, if the readings are all over the place the motor is probably ready to pack er in

agree 100%