johnson lower unit compatibility

Johnson Lower Unit Compatibility: A Detailed Guide You Need

Introduction

If you know the compatibility of your Johnson lower unit, there would be many advantages. In fact, having proper knowledge about it is a must at times. Starting from simple issues to a replacement, it is needed.

So, what is the Johnson lower unit compatibility?

The Johnson lower unit compatibility goes with the Hp series, serial, drive shaft, and shift rod. The first series of each year goes with all Hp series except 6. And the rest goes with all except 10, 18, 20, and 25. But each series goes with a different sequence. So, the compatibility differs from one another.

You have come across a brief so far. Now, get into the detailed part that would cover your concern. We got here every detail.

So, get started now!

What Is The Johnson Lower Unit Compatibility?

To understand the compatibility of the Johnson lower unit, you must consider a few things. And those are the HP series, lower unit, drive shaft, and finally, shift rod.

Because without the compatibility, there would be many issues like Johnson fuel pump issues.

So, here we go with detailed compatibility of Johnson’s lower unit per year. Have a look-

  • The lower unit of the year 1970 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1970 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1971 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1971 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1972 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1972 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25. Remember this sequence are same as the rest series.

  • The lower unit of the year 1973 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1973 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1974 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1974 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1975 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1975 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1976 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1976 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1977 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1977 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1978 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1978 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1979 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1979 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

  • The lower unit of the year 1980 is compatible with all the HP series except 6. It would have the serial of 382574 or 390040. 

The drive shaft and shift rod would be 381026 and 309582 respectively. However, the lower unit of 1980 has other compatibilities as well.

Like, some other versions are not compatible with 9.5,18, 20, and 25.

So, this is the sequence it has come up to the latest series.

What Happens If The Compatibility Does Not Match?

It is very obvious that a mismatch of compatibility would have issues. So, you can not overlook this thing while you get one.

Now, you may wonder, what would be the issues for this mismatch! Well, there would be some common ones like tachometer having issues

However, there is more than you may know. So, here you go to understand those issues.

Problem 1: Gearcase Issues

The gear may make grinding noises if the compatibility does not match. Gradually, the gearcase would start wearing out.

As a result, it would be damaged eventually. And you need to replace it at a huge cost.

Problem 2: Less Efficiency

Due to the mismatch of compatibility, your boat would be less efficient. That is, the fuel consumption of the boat would be way higher.

You would notice that the fuel finishes way before you expect. As a result, the cost of fuel would increase significantly. And your fuel filter may also be damaged.

In case you want to replace your fuel filter, here’s an idea.

Product 1
Product 2

Hope this helps!

Problem 3: Sudden Stalls

You may experience sudden stalls due to the mismatch of compatibility. Along with that, the boat may suddenly give an irregular shake when you are riding.

However, your boat engine may also stall for other various reasons as well.

So, these are the common issues for the mismatch of the lower unit compatibility.

FAQs

Do Johnson and Evinrude join together?

Yes, Johnson and Evinrude joined together to produce outboard motors. These two companies are affiliated and have been making outboards stuff since 1986. However, they are competitors at first. And then they joined together to lower the competition and share profits.

Is there a way to identify the Johnson motor?

Yes, you can identify the Johnson motor easily. You just need to locate the code number of the motor. And you can find it on the outboard part. You would see a nameplate where it is mentioned. Once you identify the motor, it would be very feasible for you.

Is it worth it to use the Johnson motors?

Yes, it is worth it to use the Johnson motors. These motors are really appreciable for their quality and use. However, the Johnson motors are a bit oil-consuming. But if you can use it well then the motor would be very efficient. And the maintenance of these motors is easy too.

The Final Words

Now you know about the Johnson lower unit compatibility! We believe you have no more confusion regarding its compatibility concerns!

That is all from me. Good Luck!

Leave a Comment

Your email address will not be published.

Scroll to Top