1990 V4 88spl Johnson Dazed and Confused

[Rod Holder]

Hi,
Been quite some time since last post (sold my 4.7 Mercruiser and got a Johnson OB!).

History:
Have owned this motor for 4 years. Used frequently, even during the winter months. Constantly running fresh fuel. Never any issues at all. Always starts well and runs great. Only slight smoke at startup. Never when warm.

Compression is not the best (110 / 120 / 100 / 115) and #3 has shown as low as 70 cold.
Replaces the thermostats this spring
Battery charge volts would sometimes get up to 17 volts (at cruise per fish sonar display)

Problem:
Two trips ago I noticed that the volts were down to 12 while cruising. Seemed odd but was not overly concerned. No starting issues. Ran great.

Again the following trip the volts were down but it started fine. Ran fine. Fished for several hours using electric downriggers. Went to start the main and would not start, sloooow crank. Ok, charging sysyem failed and I ran it down too far. Borrowed a battery from someone out on the water (were 16 miles out).

It started but was smoking way more than normal and seemed down on power, died at idle so I got it started and ran it 3/4 throttle back in, still seemed off. Sputtered and died coming into harbor.

Got it home and found that the rectifier was FRIED. So hot that the sealant dripped out.

Replaced the rectifier. Still runs like total crap. Will start but smokes like crazy when throttle is increased and sucked thru 1 gallon of gas mixed fresh to rule out fuel issue in just a matter of a few minuted troubleshooting!!! Smells extremly ripe!! Plugs are fouling as you would expect.

All 4 are getting spark. Tested all the resistance values on the stator, coils and timing plate. All OK.

Visually inspected everything short of pulling the flywheel and checking out the stator and timing plate.

At a loss here. I suspect the power pack or more so the stator but hate diagnosis by replacement ($ ouch)

Any suggestions at all would ve very much appreciated................

RH

 

[LindenLongRods]

Re: 1990 V4 88spl Johnson Dazed and Confused

Hey I have a question for you. I have an 1987 88 SPL, Love it!!! Where is the thermostat located, was it easy? (lost my manuel) Wish I could help with your issue. I changed the rectifier in mine when I first got it, easy change. I did it because I felt my batteries were not being recharged after using the engine, seemed to help, but then again I've changed my batteries a couple times. happy boating

 

[Daviet]

Re: 1990 V4 88spl Johnson Dazed and Confused

If you are getting good spark, will it jump a 7/16" air gap and be bright blue, and the compression is OK. I would look at the fuel system, maybe you have a carb overflowing and spilling to much gas.

 

[Rod Holder]

Re: 1990 V4 88spl Johnson Dazed and Confused

Thanks Daviet. I'll check the spark like you suggested. I had only checked for spark with the plugs removed and a ground wire on the threads. I was trying to focus on anything related to the electrical issue (what are the odds of two seperate systems acting up at the same time???) that was going on but yes, after seeing how much gas was literally pouring thru the engine it would make sense to make sure the carbs are ok (I went thru them a few years ago but stranger things have happened). I did check for a ruptured fuel pump diaphram and it was fine.

Anyone know if running a few hours with a blown rectifier can affect the stator or timing base?

Long Rod,
The thermostats are in the oval shaped housing between the two bottom cylinders and has a hose coming out of each end. I drilled thru the outer body to access the three bolts. Plugged the holes with stailess socket head bolts, fender washers, nylock nuts and rubber gaskets (bike tire tube). The washers conform to shape while tightening. I can take a pic if you want.

 

[Rod Holder]

Re: 1990 V4 88spl Johnson Dazed and Confused

Update:
Checked for spark and it will jump close to 1/2" and is blue. Removed the carbs and disassembled. Clean as a whistle.

Pulled the flywheel and dressed up the inner part of flywheel. The stator and timer base appeared good (do signs of overheat, but they are sealed units)

Ran it again and still havig same issues. Runs weak, coughing, smoking and abrupt stalling (especially when trying to accelerate (timing base advances properly and the timing is not erratic and can't seem to detect any spark loss at any of the cylinders)

Completly at a loss with this thing.........

 

[Daviet]

Re: 1990 V4 88spl Johnson Dazed and Confused

If you are sure the spark is OK, are the plugs OK, and the fuel system is operating properly, use a timing light to check the firing on the cylinders. The flash should be steady indicating you are not dropping cylinders.
Go to the CDI website and look up your engine and use their troubleshooting guide to help you check out your ignition system.

 

[LindenLongRods]

Re: 1990 V4 88spl Johnson Dazed and Confused

Yes Rod would appreciate a pic. Was looking today and there was a rectangular box with 2 hoses between the 2 lower cylinders, don't know if that's it or not. Still waiting for parts to replace my water pump. Mail is slow I guess Holiday. anyway thanks have a good weekend

 

[Rod Holder]

Re: 1990 V4 88spl Johnson Dazed and Confused

That's the one. Held with three bolts. Middle one can be removed with a box wrench but the other two not so much.