Johnson 90HP Repair

It shouldn't be with proper care and maintance. Why is it in need of a rebuilt kit in the first place, age ? Two weeks is long to wait for a kit. Are they that backed up and are making you wait your turn?

ORIGINAL: jon_e_si

I have a 90HP Johnson I took in for service - was told I need a carberator re-build kit (on order). It's been over two weeks. My question is - does this seem excessive and wonder if it will be a recurring problem???

2 weeks for the part or 2 weeks for the whole job?

2 weeks for the part seems excessive but when i needed some older evinrude parts, it was almost a week minimum. not sure if theres aftermarket companies that make the rebuild kit or not. most marine shops ive dealt with dont want to have anything to do with johnson/evinrude. they might get you parts but you're on your own after that.

2 weeks for the job; this time of year imo is great. most shops are swamped. just sayin'

had no idea. is merc still making the verado on its own?

Might not be alot in a 2 stroke carb, but the few rubber parts that are there get eaten alive by the ethanol in the fuel now-a-days!
Inlet seats and needles are the first to go then you get symptoms of flooding the carb.
 
That's why I run AV gas...no alcohol.
 
 

That's why I run AV gas...no alcohol.

AV fuel is 100 octane low lead-with this I could advance timing in my Checkmate 5* to 10*
Now I don't know anyone willing to sell it
old 115/145 avgas, was ultra-high octane, heavily leaded.
This stuff was dark and had a very strange odor

Turbo Blue unleaded+ has 104 octane
Racing fuel is 110 or higher-one whif of this stuff gives me an instant headache

Thanks again - that's what I was beginning to think. With my limited mechanical skills - I know it worked well with an 8HP Merc tiller I have!

Certified marine fuel has no ethanol.  Our boat club only buys fuel that has no ethanol in it.  I'll find out the supplier...  if you're in Conneaut, the Conneaut Boat Club sells it.

My boat is in the shop as well. I just got off the phone with Findley Lake Marine and they said that the carb. parts that I need are on "national back-order".
 
This will be the third weekend this summer (so far) that this problem has meant no fishing.  
 
My Merc is bumming me right the F - out.  If this is their way of getting me to buy a new one, it might work.
 
It won't be another Merc.

.notice that is is NOT unleaded...so you should only run it in older motors!

Worried about the catalytic converter?
Lead acts like a lubricant on the cylinder walls and valves.
I don't think it will do any damage

I was thinking of a carbed engine on an inboard.
O2 sensor might have problems

I bought my carb kits through iboats and they were here in a couple of days. It seems thay have combined several different carbs/years in one kit. They were cheap at $17 a piece and so it is worth doing if you are going to the trouble of taking the carbs apart. It really isn't a difficult job. Don't take not difficult as cheap to do. It is time consuming. You have to tear the carbs down, soak them, clean them, inspect them, put them back together. On a multi carb motor the work is all multiplied by the number of carbs. All at the shop rate...

R+M/2 octane method just refers to the Research + Motor octane average. It is an average of octane tests. The high avaition numbers (AV130 AV145) are from a completely different test. Supercharged engine test. People try to generalize that it is a lower octane number, and it is, but it isn't easily quantified as being x points lower. In general aviation gas is blended to operate in low speed aviation engines. I do know that people used to try and run it in high performance car engines but it really isn't designed for that and doesn't offer the performance advantages that people expect. Marine engines might be a different story. They operate closer to the conditions of an aviation engine. Lots of steady state, relatively low RPM running. Tetra ethyl lead was the preferred octane booster for quite a while and it is amazing stuff, but also extremely poisonous in raw form as well as spewing lead everywhere as it is burned. I know it is generally a necessary evil in aviation engines.

Nobody wants to experiment with fuel blends in aviation engines. You know the old joke... Pilot comes over the intercom and tells the passengers they are down one engine and instead of 2 hours it will now take three to reach their destination. A little while later the pilot comes on and says another engine is out and so it will be 4 hours until they reach their destination. Al little while later the captain comes on and says another motor has quit, but that they can limp along on the one remaining engine. Only problem is that they will be in the air for 6 hours. Finally the captain comes on and says "Bad news folks the final engine has quit." A blonde passenger throws up her hands and says "Oh great, now we're going to be stuck up here forever."

The next magic octane booster was MTBE but as that compound is a ground water contaminate the move has been to more and more alcohols. They add oxygen to the fuel, boost the burn rate, and lower the energy available in the fuel. The one thing I'm not sure about is are there more alcohols in modern high octane fuels from the local gas station? I'm not sure, but I suspect that that is the case. I also know that going around to different stations is probably a waste of time as the gasoline around here all comes out of the United refinery in Warren.

The neat thing about AV gas isn't the octane rating, but rather it's LACK of alcohol and other additives!
AV gas that you buy in Pittsburgh is the same mix as Detroit, same as D.C., same as Daytona Beach...get the point...CONSISTANCY...it has to be the same since all aircraft engines, in general, run the same.
 
Automotive pump gas is blended differently in Pittsburgh, different in Detroit, different in Daytona...due to different Oxygen and pollution fighting requirements...heck they even blend different in spring versus summer!!!
 
Yes, AV does have some lead in it, but not enough to cause problems as though you were allowing it to be run in ten million car engines!
 
BUT...the biggest thing that AV is missing is the solvents.
Do this test, take a few ounces of gas-station grade unleaded gasoline, pour it into a styrofoam cup...watch it melt before your eyes!
Now, take a few ounces of AV gas and put it into another styrofoam cup...come back in an hour and see that it is still there, then come back tomorrow and see that it will still be sitting there...yes, evaporating but NOT melting the cup.
The solvents that melted the cup are the same ones that are deteriorating your internal engine seals over years of use.
 
Also, pump gas can't sit more than a few weeks to a month before it starts to go sour, AV can sit in a can for YEARS and still hold the same quality as the day it was put in there. (I know a Merc mechanic that did this test with 5 year old fuel and paid for the lab test out of his own pocket just to proove it...and he got the lab report in print to show disbelievers!) 
 

UPDATE: Picked up boat Thursday - their verdict - water impeller needed to be replaced plus intake cleared. Apparently was running too hot - Johnson has a "SLOW" system which shuts engine down if it's too hot. I haven't had time to take to the lake to see if it's corrected. Also bought a new battery, and the exhaust ports needed cleaned! Here's hoping!