25hp johnson

Ok so I bought this outbound mounted it to boat headed to the lake it runs good but didn't seem to get to rpm. It's on a 14ft Lund with 3 batteries and two 2hundred lb guys it topped out a 10.5 mph on GPS. I was hoping for more brought home put in barrel and put on tiny tach runs good and raps up quick but wit no load I am planning on taking out tonight with the tach on and see what happens and taking out one bat will also be by myself and see what happens. Should RPM be about 5300? M# j25rleeg s# go4635313 is there anything else I should look for

What pitch prop does it have?

Enter your boat (or equivalent) and motor info (believe that reads as a 1988) into the "prop calculator" below and see what pitch prop it advises. Props are made from 9" to 15" for those motors.

See: https://forum.tinboats.net/viewtopic.php?f=4&t=37433

Otherwise wait for Pappy to chime in ... as he's the man on these motors!

Idk what prop it is. I believe it to be stock paint matches motor

Well I got it out on the water to night could get 4400 consistent out of engine on tiny tach once I got 4600 and it takes forever to get there I was by myself with no fishing gear is it carb or prop Help going to table rock lake next week end and need to be able to get around

Ok talked to my boat mech found the prop is a 13 and he says it is to steep he is going to look over engine and if can't find anything wrong he is going to change to a 10 or an 11 and the on-line prop calc says a 10.5

Well got call from mech today my Craigslist find has bent crank and fly wheel and thinks I should not spend any money on this thing. This sucks I reallliked this engine cause it was new enough to have shifter on the tiller instead of the side. So I went out and found 30hp engine I hope this one pans out. So I have a new question can I put that tiller handle and shifter from the newer Johnson on the older Johnson it looks like I could was wondering if anybody has done this the newer one is a 98 the older is like an 86

Am really doubting the bent crank thing.
Is this an authorized dealer or ? How did he determine the engine has a bent crank? Hint - You can spin the flywheel yourself and see.
Secondly, the crank, if bent, would not freely turn in the cylinder and crankcase due to the tight tolerances. Yours turned 4600 with a 13" pitch prop.
You made zero mention of any unusual engine shake while running your engine.
The engine would have shaken like Hell if the crank was bent. It would darn near shake itself apart at that RPM.
Flywheels on those engines would sometimes give a visual indication that something was not right as they will have a slight up and down movement at the edges. This does not in any way indicate a crank is bent. You want to be looking for a side to side movement at the very top of the crank while turning it, not the flywheel.
You might want to take a close look at the edge of the flywheel and the engine castings to see if your "mechanic" dropped the engine and damaged it.
Usually the motor pan will suffer damage. Will the cover fit as nice as it always did?
Unless you see where the guy dropped the engine....you do not have a bent crank.
I would never darken the doorstep of this shadetree..... ever again.

Pappy.....you are a treasure....

richg99

Ok he only works on boat engines but is not a dealer has done it for years I looked at it last night the crank may not be bent but fly wheel prolly is it wobels some and the nut on top of fly wheel looks like it is not tight cross threaded and has jb weld on it so I am sure the threads on the crank r in bad shape he just didn't think it would be a idea to spend a bunch of money trying to get it all apart to seeing what's wrong especially since I need it this weekend its not been dropped by either of us he thinks maybe it was pryed on trying to get it off the jb weld has been there a while and he called me as soon as I left with the news he never removed from boat

BRUCE1911 said:

Ok he only works on boat engines but is not a dealer has done it for years I looked at it last night the crank may not be bent but fly wheel prolly is it wobels some and the nut on top of fly wheel looks like it is not tight cross threaded and has jb weld on it so I am sure the threads on the crank r in bad shape he just didn't think it would be a idea to spend a bunch of money trying to get it all apart to seeing what's wrong especially since I need it this weekend its not been dropped by either of us he thinks maybe it was pryed on trying to get it off the jb weld has been there a while and he called me as soon as I left with the news he never removed from boat

Click to expand...

Amazing....at so many levels.
Like I said earlier, a slight up and down movement at the edge of the flywheel means nothing, zero, zip.


We have independents come in our shop all the time looking for parts, asking for information, wanting free troubleshooting help, etc, Most do not have proper troubleshooting equipment. Some change physical locations every couple of years due to some conflict with their landowner, getting arrested for drugs, etc, or a law suit from a customer temporarily puts them out of business.
Most are parts changers with a line of BS a mile long to back up their lack of knowledge until they finally luck out and fix it or the customer pulls the engine out of their shop. Ever hear about the one that told a customer his crankshaft was bent on his 25hp?
We are always getting engines in to work on that have been totally butchered by these rocket scientists in many different ways. Pissed off engine owners who have been ripped-off by these guys are often hard to deal with when they come in.
I have tried to purchase engines from these guys to get back in shape and flip. On more than one occasion the engine advertised as running had a locked up powerhead or gearcase. Twice at one "shop". Other times the engine listed was in fact up to a decade older than advertised.
The latest one we currently are putting back into service is a Yamaha 4-stroke that was found with the timing belt so far off the valves hit the pistons. According to the customer the "Mechanic" blamed this on mud-daubers. We found this out about two weeks after the mechanic had been in our shop asking how to time the cams on this engine. The customer said that the engine had simply sat up a long time and ran rough but ran prior to having a mobile guy come out and "fix" it.

This is not to say all are bad. Some are good enough to have become an independant AUTHORIZED service center. It is a buyer beware market however and before you or anyone else reading this trusts a very expensive piece of equipment to a mechanic, ask to see the manuals and electronic test equipment. Make sure the shop is clean and organized, the work will be the same if it is. Look around while you are there, is his toolbox a junk pile? Ask about any guarantee of workmanship and materials. Ask for current references.

Well this guy did me a favor by telling me to move on before wasting a bunch of money on it. The more I compare it to the 30hp I can see were some one hacked on it. Fuel lines, jb weld etc. Etc. The 30 runs great went 28 mpg in it tonight runs great that 25 is a parts engine. And this guy is the best option in my area have heard no complaints about him only good things. The local Mercury dealers won't work on a Johnson only place half way close is a cabelas and there a rip off!! I also own three businesses in the area so I always try to use local people. I have not seen his shop cause its 35 miles away and he picked up and delivered since he lives in town in a nice house with a well manicured lawn which probably means has a well kept shop. I could not be more happy with his service if I took it to cabelas I would be in the same situation only with a big bill!!