81 Evinrude 25 HP - No fuel to bottom cylinder

[willy007]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Well, when you go through and clean & rebuild your carbs you'll most likely see the issue if there is one there (either a clogged jet, passage way, dirt, or debris). If you take apart the carb and everything is clear and clean than you may have to look deeper. It's hard to eliminate possible causes without really checking them. When you do get around to rebuilding them make sure to test/check the float & make sure that the needle seats properly.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Ok that sounds good. So I got the block broken apart and pistons removed last night. See photos below. I'm not sure how tight the rings are supposed to be around the pistons when not in the cylinder, but they were pretty loose and could easily be removed without using ring pliers. With the exception of the one on the bottom cylinder which was stuck due to all of the debris. What do you guys think. The first two pics are of the upper piston, the next three are of the bottom piston.

 

[Chinewalker]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Rings are supposed to sit loosely in the grooves, with upper ring sitting even looser as it is a keystone style ring. Bottom piston is absolutely roached! If the bore it came out of isn't too badly scored, you may get by with a new (or good used) piston and fresh rings.

 

[AlTn]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

any chatter marks or "bearing shadows" < don't know the proper term > on the crankshaft?

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Bottom piston is absolutely roached! If the bore it came out of isn't too badly scored, you may get by with a new (or good used) piston and fresh rings.[/QUOTE]

Yeah, as bad as that piston looks like, the cylinder it came out of doesn't look that bad. And the funny thing is, is that all of that damage was on the intake side, and the scoring that occured in that cylinder; picture in previous post, is on the exhaust side. Any thoughts as to what could have caused that damage, or what chain of events could have taken place to allow that to happen?

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

any chatter marks or "bearing shadows" < don't know the proper term > on the crankshaft?

I'd have to double check, but I believe there is. How bad is that if there is. I'll try to post a pic tomorrow.

 

[AlTn]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

told by a reputable machine shop here," Yes, we can grind them out then polish the crank but, who makes oversized bearings for it?". I recently went through this with an 1971 18 hp. I located another crank for $65 and had it polished. If the crank has these marks, then the bearings on that rod likely need replacing too.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Alright, here are some photos of the crank. I didn't think it was to bad, what do y'all think. I was going to replace all the crank bearings and seals, and rod bearings regardless of what shape they were in.

 

[Chinewalker]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Hard to tell for sure due to glare in photos, but that crank looks alright to me. Chatter marks or rust ridges would be pretty apparent.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

I suppose I'm still not sure what a chatter mark is, but to the touch there are no abrassions or apparent ridges. Now on my to do list, is to find a reputable marine machine shop in the College Station area.

 

[AlTn]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

I'd suggest to you to call the marine dealerships in your area for referrals to the machine shops they use

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Alright, the block is in the machine shop, and they said .020 over would clean it up. So I look forward to getting it back so I can get the ball rolling with this rebuild. Next thing is to order all new bearing and seals and the shop manual. I didn't want to spend another dime until I new the block could be machined.

 

[AlTn]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

have you sourced some .020 over pistons and rings?

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

have you sourced some .020 over pistons and rings?

The machine shop the block is at, is also a WISECO supplier/dealer so I'm ordering the kits through them. However, its the same kit you can get through marineengine.com and the like. Part #3127P2.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Just thought I'd give an update. The block is still in the machine shop awaiting the arrival of the new pistons. In the interim I've received my shop manual from Ken Cook. It's pretty in depth, although some of the pictures aren't very ledgeable as they are in black and white. I think I'll go ahead and re-build the carb while I'm waiting Looking in the manual, it appears that the breakin time is only a 5 hour break in as opposed to 10 hour which I have read in many articles on line. Any thoughts on breakin?

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Looking in the manual, it appears that the breakin time is only a 5 hour break in as opposed to 10 hour which I have read in many articles on line. Any thoughts on breakin?[/QUOTE]

Any thoughts guys?

 

[nwcove]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

assuming that the machine shop will be doing the assembly? if so, i would follow their recommendations to a tee!!! jmo

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

No, they're just doing the machining. I'll be doing the re-assembly. I suppose I'll ask there recommendation though. Perhaps, since the piston set I'm getting is from WISECO, they would have some recommendations as well.

 

[likitvi]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Just a note worth remembering: Remember to pay attention to the position of the rings when installing pistons. I would assume this is well covered in the manual.

 

[cchildr84]

Re: 81 Evinrude 25 HP - No fuel to bottom cylinder

Just a note worth remembering: Remember to pay attention to the position of the rings when installing pistons. I would assume this is well covered in the manual.

Yeah, this part is pretty detailed. The top one is a keystone/beveled type ring and the bottom one is not. The ring grooves have a pin that the end gap aligns with. This is my understanding of the manual, please correct me if I'm wrong.