2003 25hp Mercury problems elec starting & idle, tried of pulling!!

[scbasschaser]

Bought my first a used boat and notice starters teeth were worn out and after a few trips to the lake if figured out several issues. First couple of starts w electric start fires ups and runs great. After making the first stop, things go down hill and problem seems to worse during the day. If the electric start is unsuccessful, then I have have to switch to pull method. The teeth are gone because of the compression build up in the engine makes pulling the cord very tight, more than a starter should be able to spin fly wheel, but after 15+pulls it get much easier and will finally crank again. Move to next spot and painfully repeat process. Have a new starter, new factory hose buti see lots of oily gunk under flywheel so I have some leaking. I'd like to avoid a major repair cost but not sure a do-it-yourself will help. Any suggestion would be appreciated!

I get sick seeing the guy crank his boat, go park the trailer, sort through tackle, tie some lures and engine purring like a cat. Painful to watch. Thanks.

 

[Bondo]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

The teeth are gone because of the compression build up in the engine makes pulling the cord very tight, more than a starter should be able to spin fly wheel, but after 15+pulls it get much easier and will finally crank again.

Ayuh,... I donno what you've got going on, but,...
Compression Don't build up in a motor...
The Compression is whatever it is, each, 'n every single stroke of the piston...

Sounds more like something is binding up...
The leaking oil might be a hint on where to look...

 

[CharlieB]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

A motor can 'tighten up' after running for a couple of reasons, lack of cooling, over-heating, a lack of lubrication, in the fuel or in the gearcase, a faulty re-circ hose or fitting failing to lube the upper bearing, which could also cause it to kill that upper seal.

Start with gearcase oil, when was it last checked, or changed, what does it look like now?

How old is the water pump and impeller, is the motor P'ing adequately?

Remove the flywheel, check for any measurable side movement in the crankshaft, is the bearing 'loose'?

Disconnect the recirc hoses one at a time, use a small syringe of alcohol to check flow, note which direction will flow, some have one-way check valves, note which is which.

Repost your findings and any further questions.

 

[scbasschaser]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

Captain, thanks for the reply. I'm not sure where to start on theses issues. I had it looked over when I bought it and because it runs great w muffs it is hard to get the tech to diagnois. Since I'm going to rebuild the carb gaskets and replace the starter as a project. can you recommend what to look for under he fly wheel around the carb. The grease and lower foot and pump should be good according to tech a marine center who greased everything.

 

[Mi duckdown]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

2 stroke or 4 stroke? serial number would help.
If it is overheating, the engine will get tight.

 

[Silvertip]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

Do you see a good stream of water coming from the tell-tale when the motor is running (in the lake -- not on muffs)? If not, you need to replace the water pump as the engine is likely overheating and tightening up. It may also be that when the starter fails to spin the engine that the battery is weak. Waiting merely allows it to recover a bit and when you next run the engine it charges again but never gets fully recovered. Don't begin throwing parts at the engine. Diagnose, diagnose, diagnose, isolate and THEN repair. Guessing gets costly.

 

[scbasschaser]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

The number is OT599667 MAA 790743, What I`m unclear about is the tightness subsides with mutiple pulls and resting a bit. It seems if what ever is binding must be needing to clear pressure or draw in water to ease the mechanism. I orginially guessed the carb do to leaking seals but cant imagine some extra gas or air binding signifcantly binding the starter. Thanks much for taking time to help with this issue.

 

[scbasschaser]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

It is a two stroke.

 

[scbasschaser]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

Silvertime, Thanks. I can see that and waiting to fix the issue before covering it up with a new part. I was told the water pump had been replaced but going to shoot some video next time out on the water. I know it can`t be the battery it is a deep cycle that is new and trickle charge each time out. I do not have an on-board charger. Is it common for a boat to pull water fine with muffs and not on a lake. Also, do you think some of these repairs can be done right using a manual and some research. I certainly don`t want to make a bigger mess of things without guideance. Thanks again.

 

[scbasschaser]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

CharlieB,
Thanks for the direction here. I`m guessing the overheating is a common problem. Since it is a night and day difference from the muffs to the lake, something is freezing up with difference in water volume. So pulling the starter chord multiple time might draw enough water though to get the parts moving again. How technical is removing the flywheel and checking under the hood, just don`t want a bigger mess with small springs, washer etc. not lining back up properly.

 

[CharlieB]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

Hose pressure on the muffs 'assists' cooling flow and can hide a faulty water pump.

Running on the water the 'P' stream should be solid and strong, motor temp should be hot enough that you can only hold the motor about 2 - 3 seconds, 140 to 160 degrees, any more is cause to start checking things closely.

Flywheel is held by a single nut but you need the correct puller, do NOT hit or pry on a flywheel, do NOT attempt to use a 3 jaw puller. The proper tool for the job as CRITICAL when dealing with an outboard flywheel as a cracked flywheel can fling itself to pieces and absolutely ruin your head.

Check here for exploded views of parts, you will need your model and serial #'s, it may help you understand what makes up your motor.

http://www.mercruiserparts.com/mercruiser_parts.asp

 

[scbasschaser]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

Thanks CharlieB, I keep you posted.

 

[M9.9]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

Here's a picture of a merc f-wheel puller:
http://www.mercstuff.com/flywheelpuller.htm

 

[scbasschaser]

Re: 2003 25hp Mercury problems elec starting & idle, tried of pulling!!

Just wanted to say you advice was very helpful. I watched alot of video and got a manual to see how to replace everything and just took it one step at a time and eliminating each issue part by part. By chance I pulled the off the uptake tube just for good measure and found a large piece of very old impeller rubber stuck way under the housing cover, would have missed it had the sun not hit the spots just right. Real blessing here. Found all kinds of old seals and worn out thermostate. Took it out yesterday and could not believe i was running the same engine. more quite, smooth, cranked perfectly and even idled fine for a long time. My hope is now restored. Many thanks.