Need help with 73 evinrude 25 hp model 25302a

[Mballo21]

Needing some help trying to figure out why motor is bogging down after running for about 30 sec at wot then once u ideal down for a few u can run wot again for a few sec have rebuild carb and fuel pump new plugs j4c new fuel tank fuel line with prime bulb and filter the compression seems low the top was 100 and the bottom was 75 any help would be appreciated thanks again

 

[F_R]

Well you have basic problem that needs to be addressed before wasting time trying to get it running right. At 75 PSI, that thing is seriously sick.

 

[Mballo21]

Well new to the boating world what would be a good place to start also I forgot say that was a cold test for the compression should I run it for a little bit then retest it also noticed that I have a pretty strong spark on top and fairly weak on the bottom

 

[interalian]

If the lower has been misfiring for a while, it could just be carboned up and rings stuck. Work on ignition then do an engine tune to un-stick the rings?

 

[James R]

Lets face it guys the motor is probably badly worn. Good compression's would be 110 and up. pulling the cylinder head would tell all.

 

[Mballo21]

Working on pulling the head but the head is stuck on there pretty darn good

 

[interalian]

Got all 10 bolts out?

 

[Mballo21]

Yea there all out seems like it's glued on there or something u can see it wanting to come off but on one side it's still tight

 

[interalian]

Need to find a way to put some force in the "away" direction - mallet and drift/screwdriver. Don't be tempted to pry between the head and block.

 

[Mballo21]

Alright finally got the head off def dirty only seen a little scuff on the bottom of the bottom cylinder gonna try and post some pic the advice def helps would a carb cleaner be good to clean the Pistons off

 

[AEROCOOK]

I had a similar motor many years ago, in fact my very first outboard. While doing a carb clean I made the rookie mistake of installing the carb float upside down. I mention this because the symptom you describe is identical to what I experienced due to my mistake. That being said, your main issue is your compression, this needs to be addressed before anything else.
Has this motor ever run well in the time you've owned it?

 

[Mballo21]

I haven't had it very long and for some darn reason I can't upload a photo keeps telling me to big but the scuff on the bottom cylinder if I run my nail over it it doesn't grab

 

[Mballo21]

No Title

 

[boobie]

Put it back together and do a good decarb on it with BRP Engine Tuner. Follow directions on the can.

 

[Mballo21]

K the new gasket won't be in till tomorrow but I will def give that a go now should I do anything else before I put all that back together

 

[AlTn]

surface the head...you can also to an extent check the rings by removing the bypass covers located on the starboard side of the engine < 4 screws hold each one on, the fuel pump is attached to one and a fuel scavenging line is attached to the other >...you'll see maybe a fifth of each piston in its bore as well as the rings..the rings should spring back in their grooves when you press on them < if you use a screwdriver put some tape over the blade so you don't scratch the rings or piston >..if they don't spring back, you may have a lot of carbon built up behind them, or the ring has a piece broken out : note the rings do not rotate as they are pinned to the pistons, anyway it's a cheap check and if you don't damage the gaskets a no cost look

 

[Mballo21]

When I put the head back on can I just use a grade 8 bolt I had two of my bolts snap off and would not like to use those bolts again if I don't half to want to use a good quality bolts thanks

 

[Mballo21]

K so when pulled the head I broke 2 bolts off one twisted out by hand which is kinda weird the other had to be drilled and tapped well got all that done and put motor back together last night took it out this morning and this thing is running good so far still need to decarb but the thing is running really smooth I wasn't able to go down to slow speed idle before now I can go into slow still need to do a little adjusting on my slow speed idle but right now I am very pleased with how the ol girl is running thanks everybody for your helpful advise