90hp Inline still trying to get him going

[Black Max]

I need some advice Clams, Laddies, anybody. I've made a few post about my trials with getting this 1974 90hp inline 6 on the water. Well here is where I'm at: I rewired the entire motor, cleaned carbs, replaced fuel lines, and changed the needle and seats in all 3 carbs. First had a problem with engine reving wide open when started them killing. I then did the link and synch from Clams and discovered the distributor pointer was off, the timing, max advance, and carb stops are all correct now. My current problem is it now idles but is still a little rough, once you put it in gear it immediately dies out. Cleaned distributor, checked spark, and plugs and all seemed okay. Spring bass fishing is just around the corner, where do I go from here?

 

[timmathis]

Re: 90hp Inline still trying to get him going

What does it idle at now ? It should be 800-100 rpm's If that is so try adjusting your carbs out 1/4 turn at a time and see if that helps your holeshot... Also check your max timing advance. What is it set at now? Please post what it is set at. Tim

 

[Laddies]

Re: 90hp Inline still trying to get him going

I am with Tim it sounds like you are down to a adjustment problem

 

[inlineal]

Re: 90hp Inline still trying to get him going

Could be the bleed restictors are missing...by 1974 they should be under the transfer covers...there are five..unused fuel is metered thru each..without the restrictors the lower cylinders get too much fuel and the idle falls off...you have to remove the covers and see if they are there..they are plastic and have a hole not much bigger than the end of a dental pick which I use to make sure they are open after installing them...I'm not sure of the year Mercury changed from external to internal but it sure sounds typical of an inline that idles poorly...

 

[jimmbo]

Re: 90hp Inline still trying to get him going

no such thing as a 1974 90hp inline or other wise

 

[Black Max]

Re: 90hp Inline still trying to get him going

At idle it is around 1000rpm's and can't get it much lower than that. The timing flashed at around 23 degrees and figure it would advance at high throttle, and the max advance is 3 or 5 degrees, my neighbor is a serious boat mechanic and that's what he told me. I'm on my own on this because he wants me to learn from my trials and troubles. I tried adjusting the carbs and adjusted until it died out then back off, doing one at a time. Once put in forward it immediately losses all signs of life. Must be looking over something, this is my first motor with a distributor and it is just killing me!!!

 

[Black Max]

Re: 90hp Inline still trying to get him going

I'm distributor stupid, and I aint lying.

 

[inlineal]

Re: 90hp Inline still trying to get him going

well..well.. jimmbo....explain what those plastic pieces that we install really are then....Funny...on the microfich page they are called "RESTRICTORS"..."5" per motor........Black Max...oh never mind...

 

[Clams Canino]

Re: 90hp Inline still trying to get him going

Originally posted by Black MAX:<br /> At idle it is around 1000rpm's and can't get it much lower than that. The timing flashed at around 23 degrees and figure it would advance at high throttle, and the max advance is 3 or 5 degrees, my neighbor is a serious boat mechanic and that's what he told me. I'm on my own on this because he wants me to learn from my trials and troubles. I tried adjusting the carbs and adjusted until it died out then back off, doing one at a time. Once put in forward it immediately losses all signs of life. Must be looking over something, this is my first motor with a distributor and it is just killing me!!!

OH!!! THE BOARD IS BACK!! <br /><br />Backwards. Max advance TWENTY ONE degrees AND NO MORE. Idle will be about 0-4 degrees.<br /><br />-W

 

[Black Max]

Re: 90hp Inline still trying to get him going

Yeah I messed up, the max advance was around 23 and supposedly the mechanic next door said that was good, and the idle was as specified. Guess I will drop it down to 21 my self and give it another go. He acted like 23 was good, but I guess he was wrong. I gave him a print out of Clams "Link and Synch" but apparently his ego got in the way and he didn't even look at it.

 

[Clams Canino]

Re: 90hp Inline still trying to get him going

Fixing the max advance won't help with idle, it'll just make it live longer at wide open. <br /><br />Older motors may have idle issues from tired reeds, or as pointed out missing bleed restrictors even on an off chance.<br /><br />If you can get the idle under 1000 on an unrebuilt oldie - you win. Try taking the mix screws out 1 turn from dieing.<br /><br />-W

 

[Black Max]

Re: 90hp Inline still trying to get him going

Actually my motor is a 1978 Mercury 90hp inline. Cranked her up this weekend and things are slowly beginning to improve. I have the idle down to around 800rpm and can rev her wide open with out it dying out. The fuel lines are jumping when shes running so my only problem now seems that I don't have enough fuel in my tank. So I'm going to fill her up this weekend and give it another go on the water. This weekend I went hunting with a buddy and he had a 90hp Mariner inline on back his boat. He got out of the boat at his spot then told me to go a little further then tie up the boat. I jumped in the driver's seat and had to see what that 90 could put out. 3 miles down the canal later I realized that that motor had some gitty up. Man that inline doesn't even compare to my old 85hp Merc. Can't wait to get mine going!!! Thanks for the reply's.

 

[timmathis]

Re: 90hp Inline still trying to get him going

Black max, I would try some seafoam in with the gas and run it a while that maybe all it needs is to run it for a while. It sure helped my mercury 150 hp inline after 10-12 gallons with seafoam it made the world of difference on my holeshot and idle. Good Luck to you, Tim

 

[Black Max]

Re: 90hp Inline still trying to get him going

Yall can call me stupid, and I have already beat myself in the head 1 to many times. <br /><br />The problem with the motor was compression. I didn't check it when I started working on it. 120/150/45/140/150/155. Number 1 and 3 cylinder had stuck rings, apparently the previous owner must have run cheap oil, because the wrist pin was even clogged with carbon due to the extent of time he must have run it with the rings stuck. Good news is I tore the power head down changed the bad piston and rings pulled another power head out of storage that had good cylinder walls, and now all I have to do is clean her good with gas, do a little polishing, and put the powerhead back together. Wet and rainy today = a perfect day to stay in the shop and play with an old Merc.

 

[timmathis]

Re: 90hp Inline still trying to get him going

No not stupid at all BlackMax. We are only human and we all look over things sometimes. Someone is lying if they say they don't. Well at least you have found the problem and have the stuff you need to fix it with.<br /> Soon you will have a true Tower of Power on the back of that thing. You just thought it had some pep!! Wait and see what it feels like with all 6 pumping hard.<br /> Good Luck with it, Tim <br /> .

 

[Black Max]

Re: 90hp Inline still trying to get him going

Well I finally got the motor back up and running a few weeks ago. I put extra care into making sure it was clean when coming up, after honing, slight polishing, building up around the spark plug holes, and swapping out exhaust baffle plates. Ran a little a rough at the beginning, then found that the bottom carb was out of synch, re-adjusted then had it running perfectly. Next day first test run on the water. Rainy day, but took it easy on her for a 8+ mile journey back down a local river system where many motors have cunked out on me. The next weekend I guess I became a little to confident and planned to go on an all day fishing trip with the old 90 and brought along my buddy in his Bullet in case something went wrong. From 8am to about 4pm she performed excellent and made me excited that I was back on the water after a long drought. To Be continued..................

 

[Black Max]

Re: 90hp Inline still trying to get him going

Continued...The outboard problem saga continues,<br /><br />At around 4:00pm we decided we better head back to the launch before it became to late. Four minutes in to our return run, at about 3000rpm I hear the motor dying out, so I turned off the ignition. Went back to rotate the flywheel and it seemed to be a little tight. Got home several hours later after being towed in for 7 miles. Next day realised that number 2 and three have around 60 to 70psi compression. (Oh not again, back to where I started.) I took the intake port covers off to see if I can detect the problem, all rings appear to be still attached, but can't really see to well. Cylinder 2 and 3 have water in them and there also appears to be water on the crank. Might tear the powerhead down again tonight to find out for sure. Powerhead was completely rebuilt along with water pump, fuel pump, distributor, and carbs. All done in my neighbors shop who is a 40 year outboard expert.<br /><br />Anyone have an idea what might have happen.<br /><br />My outboard problems continue, 3 outboards killed in 1 years time. I operate everthing with care and perform proper maintenance, but my luck the past two years has just turned for the worst.<br /><br />Back to the bank once again.

 

[ronnieboy]

Re: 90hp Inline still trying to get him going

might be pushin water in around exaust plate, my v-6 mariner had blown gasket, let exaust in at low pressure, and water in at high speed. maybe?

 

[Black Max]

Re: 90hp Inline still trying to get him going

Took off exhaust baffel cover and saw that the number three piston was apparently sloshing water because they had no carbon on the port cover. i can visually see that the number 2,3,and 4 piston has scratches at the top of each one. Looks like the problem was water , but haven't found where it came from yet. Pulling out the crank tonight.

 

[MercFan]

Re: 90hp Inline still trying to get him going

Inlineal or anyone else that can give me more info on the bleed restrictors? A pic of their location would be really helpful!