Help with 1985 70 hp Johnson

[muellerlandscapes]

Hello I am new to boating and to Iboats. I have spent the last week going through forums trying to figure out the problem with my boat but nothing has helped so I decided to post my own. I purchased a 17 foot bayliner Capri from a local guy I found on craigslist. The engine, a 1985 70 hp johnson, ran perfect in the guys driveway on muffs. Got it home and took it out the next night. I live on a small private lake in northern Illinois. I got it in the water and tried to start it. Cranked and cranked. Sounded like the battery was dead, took the battery out of my truck, no difference. Pulled it back to the house and figured the starter was done. I am an experienced small engine and truck mechanic so Im no idiot to engines. I cleaned the starter out and flipped the brushes and put it back together. Started right up in the driveway first turn. Took it back out to the lake for a romantic night cruise with the wife and then the other problems started. I can usually get it to start with the throttle all the way down and with the key prime but as soon as I would bring it back to idle it would just die. Figured out how to adjust the idle but after I bring it back to neutral to put it in gear it still dies. Frusterated I put it back on the trailer and gave up for the night. Spent the next day going through forums and it seems like this is a common problem. That afternoon I bought a fresh tank of gas mixed it 50 to 1 added sea foam after reading someones post about it. Replaced the spark plugs gapped to .30. Ran perfect in driveway again. Took it back to lake. Starts right up but same problem with putting it in gear. Now pissed off I let it rev for a minute and quickly slammed it into gear and gunned it and it stayed running. Drove it around the lake for half hour just above idle and it felt good. Had to keep it just above idle to keep it running but it did stay running. Felt better but still had my doubts. Took it out two days ago and seemed to be a little better but we figured we would see what it could do now and got it up to 30 mph. Ran good for about a minute but then it seemed to starve for gas and would cut out when accelerating. Seemed intermittent. Would slow down give it gas it would pick up then bog down. Then all of a sudden it wouldnt go much over idle and we limped back to the trailer. Now after its been running it is easy to start and will idle pretty good. Lets me shift without dying but now I'm even more Frusterated. I went on Iboats and ordered a seloc manual for the engine but it wont be here for a few days. Like I said I'm a decent mechanic but these outboards are a different animal. I am having family over on Friday and I would love to have this running to take them out. Please help me. Any thoughts or suggestions would be very appreciative.

 

[eavega]

Re: Help with 1985 70 hp Johnson

First thing you should know that a motor running on muffs has no backpressrure on the exhaust and thus may run perfectly on your driveway but fall flat on its face in the water.

I would tell you that the first thing you should do is a compression test to make sure you are getting good, even compression across all three cylinders. You should also do a spark test to make sure you are getting adequate spark (I believe spark should jump an 7/16 air gap using a spark tester, and spark should be a bright blue bolt).

Next thing you should to is probably do a full rebuild of your carburetors to really clean out all of the orifices and jets. Chances are you have some crud built up. The new fuel and sea foam may have helped where the fuel can actually manage to flow in the carburetor, but if if varnish or gum has gotten up into an orifice, then fuel is not flowing and its still plugged up. My gut feeling is that the high-speed orifice might be plugged up (which would kill your acceleration). When it ran good you were probably moving fuel, but something got in there (varnish, gum, crud) while you were running and has now plugged it up again.

Lastly (and as part of the carburetor rebuild you will do this anyway) to properly link and synchronize your carburetors.

Rgds

Eric

 

[muellerlandscapes]

Re: Help with 1985 70 hp Johnson

Thanks for the quick reply. Do you think I will need to purchase a carb rebuild kit or get away with a cleaning? I had read about the backpressure and the muffs but I still wonder why it wont idle until it is been running in the water for awhile. I keep reading about a link and sync procedure. Do you think I need to do this. For what its worth the guy I bought it from "said" he had it out the two previous weekends with no problems and sent me pictures with them out on it so I doubt that whatever is wrong with it is a major problem.

 

[eavega]

Re: Help with 1985 70 hp Johnson

If it were me, and I was going to tear into the carbs to clean them out, I would want to make sure I didn't have to do it again and would do a full re-build.

Link-n-synch is a fairly straightforward process, but if your carbs are out of synch, you may find a situation where the butterflies are not in the right position when you are at idle, which could cause idle problems. If the unsynchronized carb continues to be out of synch through the full movement of the butterflies, it will cause problems at all throttle ranges. Besides, if you do the carbs even just to clean, you will have to do the Link N Synch anyway.

one thing I forgot to mention; get the OEM manual. The Seloc is a little too general sometimes and downright inaccurate at others.

A thought and it may just be my suspicious nature; every used boat/motor I have ever bought were in good running order until I got them. They had been out on the water a week or two ago, the fuel is not stale, the impeller is fairly new, the carbs were just serviced. I've learned that when it comes to being a buyer, "trust but verify"

Best of luck

Eric

 

[muellerlandscapes]

Re: Help with 1985 70 hp Johnson

I know how that is with buying things. I wheel and deal with mowers and trucks and small engine stuff all the time but I also can test them on site usually so I know what im getting into. I wonder if most people would make a seller show them that it works in the water before buying it..... I tried to get a oem manual from this site but they dont offer one. They only offered the seloc one. Maybe ill try a different site or ebay. I even called iboats and verified and the guy said thats all I they had for that year. I was wondering about a fuel pump. I dont seem to see one on this engine and I got ahold of a napa marine parts book and they dont have any listing for a fuel filter or pump for this engine. I know with so many different engines out there its impossible for someone to know everyone but it seems to me that it would have to have a pump and filter???? Thanks again for your help. I ordered three carb rebuild kits from napa and they will have them tomorrow.

 

[starcraft69a]

Re: Help with 1985 70 hp Johnson

I would check spark I had a similer problem and a cylinder down and it was the coil. All the above is correct but befor tearing into carbs I would check spark.

 

[eavega]

Re: Help with 1985 70 hp Johnson

I tried to get a oem manual from this site but they dont offer one. They only offered the seloc one.

Yes, your best bet here is ebay for a used one. I think there is an online source for OEM manuals, but I don't recall off the top of my head what it may be. iboats does not carry the OEM manuals for older motors.

I was wondering about a fuel pump. I dont seem to see one on this engine and I got ahold of a napa marine parts book and they dont have any listing for a fuel filter or pump for this engine. I know with so many different engines out there its impossible for someone to know everyone but it seems to me that it would have to have a pump and filter????

I believe the 1985 uses the VRO pump. If you look at the parts book, look for the VRO pump.

Rgds

Eric

 

[muellerlandscapes]

Re: Help with 1985 70 hp Johnson

Update: I took it out last night. Fought with it for over an hour to get it to start. Finally took plugs out cranked it a few times put them back in and got it to turn over. Died again. Finally figured out that it starts first crank if I just barely put the prop in the water give it half throttle no prime... Drove it for two minutes going maybe 3/4 throttle started bogging down. Limped once again to dock. Today I drained the three carbs instead of a full clean, trying to get lucky and I didn't have much time, and I cleaned in line fuel filter. Found the fuel pump and I dont think this is a vro engine maybe it was but there is no oil tank. Had family over today thought I could catch a break for once and took it out again today. Tried my new starting technique fired right up. Accelerated fine then 30 seconds later fell flat on her face. Drove around like an idiot for an hour. If I gave it ten minute or so it would let me accelerate for a few seconds then bog down again. Idles fine. I came home and looked up this engine on iboats for a fuel pump and there is no list for it. I guess unless this added info someone has a suggestion my next step will be carb cleanings this week. My gut feeling seems to lean toward fuel pump but having no listing for it I dont know where to go now. I am including a link to the iboats parts listing for my model hoping this helps someone help me. Thanks again for anyones help

1985 Johnson J70TLCOS 70 hp Outboard Motor Parts

 

[eavega]

Re: Help with 1985 70 hp Johnson

I'm not familiar with the procedure as I have never had a VRO engine, but I do hear often of them being converted to using regular pre-mix. I'm not sure but I believe it involves adding a non-vro fuel pump. You may want to search the forums for VRO Conversion to get a better clue, but I think in either case the pump is driven by crankcase pressure. Try and trace back from the carburetor fuel lines to what should be the fuel pump. Fuel pump should have one hose to the carburetor, one hose from the fuel line connection in the lower motor cover, and one line to the crankcase. Whatever those lines connect into would be your fuel pump.

Rgds

Eric

 

[muellerlandscapes]

Re: Help with 1985 70 hp Johnson

I found on another website a picture of the fuel pump and it looks like it is still the vro pump but I do not have a oil tank. We have just been mixing the gas. I guess my next step is to check the fuel pressure. I dont know if anyone has an idea what the pressure should be? tonight I will take some pictures and maybe someone will have a suggestion for me. Thanks again

 

[muellerlandscapes]

Re: Help with 1985 70 hp Johnson

Ok I have figured out quite a few things in the last few days. The fuel pump is a vro2 but I do not have an oil tank. The oil tank hose is not capped someone just took the hose off at the connection and left it. I have removed the pump opened it up. Seems to be in good working order to me. I am gonna reinstall it tonight after I have capped the oil line and replaced the fuel filter. I am wondering if this could be my problem all along? After a good cleaning of carbs and new filter and all the other things I have done if I still has problems what would be my next step? Anyone with suggestions would be very appreciated.

 

[AlTn]

Re: Help with 1985 70 hp Johnson

the compression test will help you decide how much time/money you want to put into this engine...next would be a spark test, must jump a 7/16" open air gap...then to fuel delivery. I've read many posts for converting from the vro pumps to standard fuel pumps on the 70 hp. models. Seems like there was something under the Top Secret Files at the beginning of the forums on this.

Try marineengine.com for parts diagrams of your motor as well.

 

[muellerlandscapes]

Re: Help with 1985 70 hp Johnson

Compression was good. Spark is good. Checked all of these first. Reading some other posts something caught my attention. Under the flywheel there is black melted plastic or rubber. Looks like it dripped from onto of the engine. Another post says this is from the stator? Could this cause my problems? If this is from something related to the charging circuit I dont really care that much. Ill just keep charging the batteries until its running perfect. My question in my previous post I am still wondering about. If the oil side of the vro pump was sucking air could this have caused the problems I am having?
Thanks for your help

 

[eavega]

Re: Help with 1985 70 hp Johnson

Oooh, black melted plastic COULD be your stator, but that is not just the charging circuit, that is also producing your spark. My understanding is that if you had destroyed your stator, then you would have no spark. On the other hand, electronic components are notorious for working some of the time. As they warm up and expand, something grounds out or arcs and leaks electricity. You could run the engine on the water and when it starts to bog down, put a timing light on it to see if you are losing spark on one or more cylinders. That would indicate a situation where something is grounding out or arcing when warmed up. Your best bet would be to find the CDI troubleshooting guide, and with a DVA-equipped multimeter check your ignition components. the CID toubleshooting guide has tests for the stator, as well as the power pack.

I don't know anything about the VRO pumps, but since all the conversions I have heard about involve capping the oil line, I would assume that having it just hanging there is not a good thing. Would that cause your symptoms? Unknown. I believe the oil side utilizes its own pump.

Rgds

Eric

 

[AlTn]

Re: Help with 1985 70 hp Johnson

try the site maxrules.com for vro/conventional fuel pump questions and ideas

 

[muellerlandscapes]

Re: Help with 1985 70 hp Johnson

After cleaning and inspecting the fuel pump I reinstalled it. When I prime the bulb gas seeps from around the mating surface. I tried to tighten the screws but the pump is so old the plastic won't take much more torque before breaking.I would like to just replace it all together. After some googeling I see that amazon sells replacement no vro pumps but there are a few choices. I wanted to know #1 where would I mount this new pump and #2 does anyone know what pump would work best and #3 the new nonvro pumps come with a built in fuel filter can I use both in line and built in for extra filtration?
If there is anyone who can help me I would really appreciate it.
I tried maxrules thanks for the suggestion

 

[Whitetail55]

I have a Johnson 70HP VRO engine on an old boat I am restoring, thankfully the VRO is already gone. Take that VRO fuel pump off and buy a regular fuel pump without oil injection. If anyone has a VRO engine convert it to premix, throw all the VRO stuff in the trash! Mine shows signs of powerhead rebuild and has great compression, probably locked up when oil pump failed. There are probably 25-30 or more VRO pump part #'s each one replaces the prior. The oil tank sits on the floor of the boat and the pump is not strong enough to keep a good flow of oil. I had a '85 40HP VRO, thankfully my hearing was better then and the high-pitched warning horn was loud enough. The oil tank on the floor was filling with gas and replacement VRO pump was around $500 back then, the pre-mix pump was $25-$30, no brainer. Good luck, these engines are good when running right!

 

[racerone]

Likely solved the issue 9 years ago !!!