New guy here.

I have been seeing an increasing number of mud motors where I hunt in AR. They seem awesome, but I have many questions.

After reading for a while on here, it seems like the capabilities of a mud motor, which are awesome, are often negated by reliability issues. Is this accurate? If so, what are the most common issues, and why are issues with mud motors seemingly so much more prevalent than with outboards?

Also, it seems like many (most) people with mud motors are constantly having to tinker with them to get them right...i.e., adding parts, changing things, etc... Is this accurate? If so, why? And are there setups that perform properly right from the factory?

Many more questions to come regarding boats and motors, but I thought I'd start here.

They're junk. Stick with the outboard.

^^^

Welcome!

As with most things in life, you typically only hear about the bad stuff. This site is no different, in that most are posting here to find help on a problem they're experiencing, so it appears that there are a lot of issues wth mud motors. As a percentage, the number of units in the field with no issues is (IMO) much greater than those that have problems. You will probably never read a post from someone proclaiming their unit just hit 500 hours without a single problem (just a euphemism terds).

Being an avid bass tournament participant and a regional manager for a major tournament trail in a previous life, I can assure you, outboards have their issues too. I've seen many pop a cork with very few hours on them.

If you decide to go mud just remember.....treat it right, and it'll treat you right.

Where are you hunting at in Arkansas?

I responded to some questions on another forum and will re-post here:

Ive just heard some bad things about these motors but it is still the motor i would like to go with.

When you read 'bad things' about a model/motor, I would look at the source of the information. You can find all sorts of negative information and horror stories about all of these motors- all models/manufacturers. They run in tough conditions- stumps, mud, laydowns, etc... not the clear water that most OB's run in.

So my question is what usually fails on them?

Common failures would be switches, ckt breakers, or trim relays (anything electrical can fail) but these are easily to troubleshoot and replace if needed. ...Common wear items are props and throttle cables.

Properly maintaining- greasing the outdrive during your annual mtc (oil change, valve lash check, greasing the frame components, check lower unit seals, muffler and case cover bolts, Checking the outdrive drain plug to ensure the lower unit seal is good and there is no water in the belt housing ...) is usually enough.

If you run sandy or sandy/silt areas you will want to keep and eye on your lower unit rear seal, sand is the devil on seals and props so do a check when you do your annual mtc (there are posts on this site that go over it in detail) to keep water out of the drive. A common new surface drive owner mistake is to trim down and grind out in sand/sandy silt- this can toast a prop in minutes wearing the cup off the end and sharpening the edges where you could skin a deer with it. Its sometimes better to walk the boat out a few yards than dig out in sand- your prop and wallet will thank you.

The Briggs big block v-twin motor has a couple of anomalies which are not specific to any brand of motor using these engines. Valve leakage and case cover gasket leakage. Valve leakage robs power and would require pulling the heads and having the valves recut/reseated- a compression test and leak down test will let you know if there is a problem. Case cover leakage is usually the result of case bolts vibrating loose. Oil seepage around the oil ports on the side near the oil filter is common, in extreme cases if running with the case bolts loose the cover can shift and crack.

These motors have a low pressure fuel pump (1-2 PSI), any air leakage in the fuel delivery system can cause problems. Common points of leakage are cheap primer bulbs, quick disconnects on the fuel tank, water separators, and loose fuel line clamps. You can read countless threads on-line about this and its not specific to any brand of motor and is usually the result of adding or changing something in the fuel delivery system.

Also any advice or things you do to make the motor last longer would be appreciated.

Regular engine mtc- change the oil and filter annually using a good high zinc oil (Boat Dr likes Amsoil 3000, diesel engine oils have higher zinc which works well for flat tappet lifters used in these motors. You can also get a zinc additive from a motor performance shop.) Change the fuel filter, clean the air filter/pre-filter, check the valve lash, lubricate the throttle cable, properly grease the outdrive, check belt tension, check the seal on the outdrive and belt housing.... A good check list of items to do before the season or putting the motor in storage for an extended period. Run good premium fuel in the motor.

In many areas you can only get ethanol blend fuel, having the motor sit up for extended periods with stale fuel sitting in the carb bowl can cause issues. Many people run Stabil or equivalent in their tanks, I personally have not had problems with this.

One thing you can do preventative for the case cover bolts when you get the motor is to remove the case bolts one at a time, clean the threads in the hole and on the bolt, reinstall with a stainless lock washer and red Loctite, torqueing it to spec (200 in lbs).

A lot of information and not meant to overwhelm you, but I tried to answer your questions as completely as possible. There are hundreds of these motors out there and most give years trouble free service if properly maintained.

Insight is much appreciated and making me feel better.

Sounds like many/most of you guys are doing your own service/maintenance, and it sounds like these motors are far easier to do this type of work on compared to an OB.

Many more questions to come.

Quick question to add some detail. So many post on the forum suggest performing a compression test and leak down test. What should compression be and what is tolerable on leak down?

Compression should be within a couple psi on each cylinder. Uniformity is what you're looking for there.

Leak down...i think briggs tolerance is something stupid like 90% I think once it got to the 30's i'd be trying to get it fixed, personally. Less the better, but most engines seem to still run okay up into that range. The seats on a briggs are going to walk, just have to deal with it, otherwise you could be doin valve jobs at every oil change,

CB
I have never heard of valve seats "walking". Please explain. We may have different terms for the same thing.
Thanks
stu

Warping, shifting, not staying true..etc.

OK got it. thanks.

No worries. Correct if you disagree. That's just my opinion on the matter, and we all know what they say about opinions. Especially mine