79 evinrude 85hp crossflow, running bad

[coolbri70]

sunday I was waiting my turn at the ramp to take the boat out and the motor stalled, it restarted but stalled again, would not idle:blue: so when I got it home I pulled the plugs they were dirty and the gap was almost 50 so I bought new gapped to 40 and installed this evening. after I was done I was looking over the fuel lines and spotted a 2" crack that was wet on top of the one that goes to the bottom carb, I pumped the ball till it was hard and could see fuel oozeing out of this crack. so I want to change all the hoses and being thrifty:greedy_dollars: am thinking of using bulk by the foot hose from the automotive store, I believe it is 5/16 thinking 2' will cover it. will this be ok, or should I buy the precut pieces from evinrude? would really rather go the $3 route and save my money for boat gas:noidea:

 

[itsaboattime]

That's what I did. Cut my hoses myself with tin snips.

 

[emdsapmgr]

I'd be careful when trying to substitute bulk hose on that engine. Bulk hoses are fine in some places, but it does not like to be bent into a tight radius. When it is bent around a tight corner, bulk hose tends to kink and will absolutely restrict fuel flow. That could cause a lean-running condition-not a good thing. The factory avoids that problem by specially heat-bending certain fuel hoses on that engine. Those hoses all have special, separate part numbers. From the original factory parts lists, there are 3 of these special hoses shown: 320947, 322701, 324079. Two on the intake manifold page and one hose on the fuel pump diagram. I'd contact a Bombardier dealer and order one of each of these hoses. They will update the part numbers and give you the 2014 equivalent hoses. They will be ethanol-compliant hoses, too. Use bulk hose in the other areas. Check out the original factory exploded parts diagrams at: epc.brp.com

 

[coolbri70]

I went with the bulk hose from the parts store, I bought 2', was $2.73, I looked up the oem parts, only 2 of them were available and it would have been over $40, got it done after work today, made sure not to kink any of them and had 3" of hose left over, had to remove the carbs to get to them. the old hoses were all dry and brittle and cracked every where. the filter screen was very clean, glad I did them all, think this will make a big difference. pumped up the primer hard , no more seepage.

 

[emdsapmgr]

My Bombardier Parts and Accessory guide indicates the gap on the spark plugs should be gapped to 030.

 

[coolbri70]

I did some searching on forums and read 40. now after further search am finding 30. some say 30 some say 40 if a lot of trolling??? I do a lot of trolling. maybe I should set them to 35???

 

[emdsapmgr]

Some of the early crossflows (mid 70's) used gapless plugs. The j-gap plug was used in your year. Those were .030. By the late 80's they had gone to low compression heads and the plug gap was .040. I run my 79 85 hp engine at .030.

 

[coolbri70]

No Title

:blue:yeah, the fuel lines and spark plugs aint going to do it, it still runs like carp, I pulled the wires one at a time and the top right made no difference, and I noticed I had water dripping from the exhaust cover where the tell tale comes out, so I pulled the cover off, while it was off looked in the ports while turning the motor by hand, spotted a chunk of piston missing between the rings and piston face:facepalm:

 

[coolbri70]

I pulled the head for a better look

 

[coolbri70]

No Title

 

[Bosunsmate]

ouch, have you rebuilt one before?
dam this forums tech is still running bad, was keen to see the rest of those photos

 

[coolbri70]

this will be the 1st for me, the forum is running very slow, not sure what to do, if I just do the bad cylinder or complete rebuild

 

[coolbri70]

this forum has allways been my favorite, but I will need help and this isn't working, I will have to start a thread elsewhere for this:blue: I know of another place some of the jonnyrude people hang

 

[Bosunsmate]

Its being the result of a real bad upgrade probably well over a month ago now, must of made a real mess in their tech system somewhere as eve since they have being working on it to fix it back up it hasnt got any better.
well back on topic. yes go for it, its a two stroke so not too complicated, heaps of people here have done them.
I did a 82 90hp a few months back, its a very similar motor.
It was the bottom starboard piston that had done exactly what looks like that one has.
I did the rings on the other pistons but you can easily get away with just replacing that bottom piston.
Get yourself some vernier calipers ($10ish) so you can measure the old piston up so the second hand dealer or shop will get you are proper match.
If you want to do it properly id get a gasket set and do all the gaskets.
First thing to do is to see what that cylinders bore looks like, if you intend to do the headgaskets again (I recommend doing that as you should replace the water deflectors around the cylinders too) then pull the head for that cylinder and inspect the bore. The one i did had only a small scratch on it by the exhaust port which i just sanded out, i should really of bought a $15 honer. If the cylinder wall is really bad you will need to get it bored out or if its really bad itl probably be scrap.
Fortunately i find that if its rings that go its normally only the softer piston thats stuffed

 

[coolbri70]

that's what I was thinking, from what I could see the cylinder didn't look bad, been pricing stuff already and looks like around $300, 1 for the piston kit, 1 for the other 3 ring sets and 1 for the gasket set :noidea: also shopping for cheap project boats, with working motors, maybe upgrade to a 115, found one on a thunderbird in Baltimore for $500

 

[Bosunsmate]

Thats not too bad, the sierra/ BRP importer here would double that and make it $US600 here at least.
Id recommend doing the rebuild, that way you know what you have and its quite interesting seeing what goes on inside the crankcase.
The only problem i find rebuilding motors is removing the bolts that hold the pwerhed on from underneath. In NZ no where is over 150miles from the sea so they are all mostly stuck in there, i coat all mine in antiseize and back them in and out every few years

 

[Bosunsmate]

Also if you do chose to go ahead with it, open it up first so you can check nothing else has gone like the main crankshaft journals.

 

[coolbri70]

I will take it all apart before I order any parts, just to make sure it doesn't need more than its worth

 

[emdsapmgr]

Yes, you can replace just one piston. However, you need to replace that piston in kind. I would not mix pistons from different manufacturers in one block. If you have all factory pistons in it now, you should replace the bad one with a factory piston. You want all of them to have the same expansion rates (when heated up) and all weigh the same. If you get into oversize for any reason, they weigh the same as stock sizes.

 

[coolbri70]

I think I just about have the powerhead off broke the head off one of the long bolts, but I think if I can lift the powerhead off I can get that one with some vise grips, what a pita