89 90hp johnson -no power

[eric fairbanks]

Well, here we go. 90 hp '89 VRO V-4 powering 17ft lund tyee. End of last season no oil alarm would come on at low (idle) speeds, but would only do it occasionally. This year it has done it a few times--usually turn motor off for fear of damage then start back up to get home and will not do it for awhile. Anyway, another problem--related? I don't know. Recently it has no power out of hole bearly gets on plane and struggles to do so. And has gotton very hard to start(this started last season). So I replaced plugs, fuel lines, primer bulb and filter, fixed a gas leak at the tank sending unit. Still no power to get on plane! This boat used to get to 40mph at 5,500 rpms, know only 30mph at 4,700 rpms! It may start easier now--but I can't tell now--hence 3rd problem--I broke off one of the plastic nipples coming from the primer and had to plug it--so now only able to prime two cylinders! Any ideas on trouble shooting the power loss problem? I can fix the primer(probably need to replace). And the oil alarm if it gets worse I will just eliminate the VRO. This is a nicely rigged walleye boat that I use alot but take care of (it looks new) But if the motor is toast I will derig it and sell it. One last thing the motor since I bought it two years ago has made a "clicking noise" at idle speed--it doesn't do it any other time--or atleast you can't hear it. I have accepted it as normal--but I know my old boat '90 70hp johnson vro did not do it.

 

[eric fairbanks]

Re: 89 90hp johnson -no power

Reply to my self, forgot to tell ya--when I'm low on power sqeezing the bulb or using the choke(primer) did not help! It there a pick up screen in the tank? Now that I think about is there a pick up screen in the oil tanl also?

 

[JB]

Re: 89 90hp johnson -no power

Howdy, Redneck.<br /><br />Your engine is behaving as though it is running on three cylinders.<br /><br />Crank it up on the muffs and pull each plug wire in turn. If there is one that has no effect that is the bad cylinder. Try swapping coils with a good one and see if the trouble follows the coil.<br /><br />Usually on those big V4s a carb problem will affect two cylinders (side by side) and a powerpak problem will affect one bank (left or right). There is some chance that you are missing two cylinders.<br /><br />If you have a dead cylinder but still have good spark to it run a compression check.<br /><br />If it is not a dead cylinder problem you may have fuel starvation. Your idea about checking the pickup in the tank is good. Also check the fuel lines, filter and fuel pump.<br /><br />Good luck.

 

[DJ]

Re: 89 90hp johnson -no power

Redneck,<br /><br />JB, is right on. I hope you haven't toasted a cylinder. Do what he said, if not conclusive, do a compression test. All cyl's. should be within 10-15 % of each other.<br /><br />The clicking sound you're hearing is probably the VRO pump, they click like that when they are starved for fuel. Take a good look at that tank. I would pull the pick up tube out of it and have a look. Don't discount a bad fuel hose either.

 

[eric fairbanks]

Re: 89 90hp johnson -no power

Gentlemen, you were right on, I started engine and started pulling plug wires--all except one made engine stall. Compression in that cylinder was 35psi! All others were 126-127psi--the cylinder is toast!! Now what? Rings? Piston? Head gasket? I have an extensive tool box and have rebuilt car engines and 4spd trannys--but an outboard? To many special tools? What is involved with a piston ring job.

 

[chumbucket]

Re: 89 90hp johnson -no power

REDnick Whats your email ?? thank you

 

[eric fairbanks]

Re: 89 90hp johnson -no power

E-mail is efairbanks@tcco.com

 

[DJ]

Re: 89 90hp johnson -no power

Redneck,<br /><br />Sorry to hear that. It sounds like you can handle it. I would get the OEM shop manual from a local dealer. It will explain-EVERYTHING.<br /><br />Once you get it rebuilt, you'll need to find out WHY that cylinder cooked. Really, only one thing causes it-HEAT. More than likely from a lean condition. Possibly-overheat. Which cylinder was it? Was it the (looking from back of boat) the top right side? That's the last one to get cooling water.

 

[DJ]

Re: 89 90hp johnson -no power

Redneck,<br /><br />I reread your last post and I missed something my first time around. Pull the head on that side. If your engine did overheat, or got close, you may have just popped a gasket. I had an 89 90 hp. that did exactly that. I got a lilly pad leaf wrapped around the intakes and didn't notice it until my hot horn went off. Too late, blown gasket. Limped home with only about 2/3 normal power available. Sound familiar?<br /><br /> By the way, is the spark plug on the cyl. with low compression very clean? If so, it's the gasket. About $40.00 and your back in biz. Now to find out why the warning horn is going off.<br /><br />Good luck!

 

[eric fairbanks]

Re: 89 90hp johnson -no power

If you look at the back of the engine it is the bottom left cylinder. No, never had the "hot" alarm go off, but I think the cylinder was weak when I bought it last year. I remember now the owner telling me he had to use the kicker motor to get home once! You learn as you go--this is my fourth boat--and if I ever buy another used one I will run a compression test on it! The plug on the dead cylinder is cleaner than the rest but not real clean. I was wondering about the head gasket--I will pull it tonight--can't hurt it now! An OMC tech on another forum said it needs an overhaul, pulling the head should tell the tail (ie. if the piston has a hole or rings are toast.) The alarm is the VRO alarm, which if I decide to fix the motor will fix or eliminate the VRO before I run it again! It could be that the engine runs so rough and idles bad that bad vacuum could be causing poor/low oil circulation, it does get oil, you can see it running out of the exhaust due to not being burnt in the dead cylinder. But I believe the VRO requires vacuum to work properly.

 

[DJ]

Re: 89 90hp johnson -no power

Redneck,<br /><br />You've got the right idea. Hope it works out well.<br /><br />On mine, when I took the head off, I could not find where the leak was. I came to find out that the head was not torqued correctly. I based that upon the other side in which ALL the bolts were loose. It was waiting to pop too. That "breif" overheat just opened up the weakest link in the sealing surface.<br /><br />I installed a new gasket, retourqued both sides (inch pounds) and never had another problem. In fact it ran better than new.<br /><br />I completely trust the VRO system. You have verified it is in fact using oil. This is what I would do.<br /><br />1. When you finish repairs, pull and empty the oil tank and replace the sock on the pick up.<br /><br />2. Reprime the oil system.<br /><br />3. Run premix until you can verify, again, oil useage from tank.<br /><br />4. DIG INTO THAT FUEL system. It think you may be starving the engine somehow. Don't forget about the tank air vent circuit!

 

[DJ]

Re: 89 90hp johnson -no power

Redneck,<br /><br />What did you find when you pulled the head?

 

[eric fairbanks]

Re: 89 90hp johnson -no power

Pulled head #4 piston/bore is toast, piston slapping in bore--bore is grooved real bad. Piston right above it is perfect can still see cross hatching in bore. OMC mechanic is telling me 1500-2200 to rebuilt it(just power head)--depends what else he finds when he gets into it. He also has same (entire motor) rebuilt that he could sell me for 2,600. I'm tossing around the options--a new 90 horse is 5,600.

 

[Franki]

Re: 89 90hp johnson -no power

Well, I am probably the least experianced person thats posted so far with regards to rebuilding.. but I can tell you from what I have read here, and heard from my local outboard mech,, that its quiet acceptable to have pistons of different oversizes in the same engine with 2 stroke outboards..<br /><br />So if all your other bores still have cross thatching then it might be cheaper to just get that cyl bored and put in an oversize piston.. no point replacing stuff that aint broke.. <br /><br />But before you go and do that, I'd be wanting real bad to find out why that particular cyl self destructed so you don't do it again..<br /><br />Is the bore so clagged that it couldn't be bored out? ie does it need resleeving???<br /><br />you might get out of it alot cheaper then what you just quoted.. particularly if you do the manual part yourself.. (ie deliver the block to a machinist, get it bored, and do the dis/assembly yourself.)<br /><br />regards<br /><br />Frank

 

[chumbucket]

Re: 89 90hp johnson -no power

Rednik go for new one almost half price for rebuild .Coarse easy for somebody else to say. Bought new 50 rude in 87 dont regret still running on 16 footer.Next year Looking for 150 for 20 footer. Its like say pay me now or later