Wanted: 350 MAG MPI Motor for 2001 2300V

[Djimax]

Wondering if anyone out there has a 350 MAG MPI motor to go in a 2001 2300v. I think my motor either needs to be rebuilt, or replaced. Looking at all options and prices.

[boatwakes]

I have a machined block, crank, cam, pistons, intake etc. Been sitting for years so needs to be cleaned but OEM mercruiser shop did the machining. Needs to be assembled. $1000.

[cltTige]

^that's not a bad deal. Where were you when I needed a new engine?!?!

Other options are Atlantic Marine, Jasper (great product, but pricey), Marine Engine inc. (IIRC there are a lot of mixed reviews about these guys), MarineEngines4less, Michigan Motorz, and prob more. If I had to do it again, I would honestly just go pull a 5.7 out of the junk yard and slap it in there. Lots and lots of research has led to different debates on if/what internals are different. After research and talking to guys that refurbish these engines, the only noticeable internal difference is the cam shaft (this is prob going to start an argument). So if you wanted to take the time, pull a low mileage engine, swap cams, and whatever else is needed when you do.

[tigemech]

Whats wrong with it? For that motor find a good reliable machine shop in your area and just have them rebuild it. That will probably be the cheapest option. And if anything goes wrong with it you bring it straight back to the place that built it instead of having to ship the motor.

[Djimax]

Thank you everyone so much for the quick responses! I'll definitely look into all options... including your machined block, BoatWakes. So here is/are the issues I'm experiencing with my motor...

First and foremost, it is my understanding that this motor should EASILY see 4500-5k rpm, however, I'm maxing out (WOT) at maybe 3800-4k. I know my motor eats oil... it has been since I bought it (06/2015). However, just this past summer I started experiencing a new problem. At startup, my oil pressure is within allowable range (meaning it sits at/or above the lower tick-mark on the gauge). As I run the boat, my gauge reaches the center tick-mark. Once the motor is warm - meaning, I've ran the boat at 2500-3K rpm for more than 10ish minutes, I experience a strange problem. If I bring the boat directly to neutral or idle, my oil pressure drops through the floor, the alarm goes off, and sometimes the motor will even shut off. If this occurs, I can put the boat in neutral and rev the motor, and oil pressure will come back up to an acceptable range. Strangely, if I eeaase the throttle back, I can maintain enough oil pressure so that the alarm doesnt go off and the boat stays lit. I should mention here that I am running a single-weight oil and the motor has EASILY 600 hours on it.

I'm no mechanic, but my initial instinct says oil pump or pickup. But if it were only the oil pump, then why would the motor be eating oil? Why would I only be getting maybe 70-80% of the rpm? Why does my boat have trouble planing out with 10 people and no ballast (I would imagine it should be able to do this with ease)? It feels to me like the clearances in bearings, rings, and other journals have expanded, and are allowing oil to seep through.

As always, I appreciate any and all help in the matter! You guys rock!

[chpthril]

For an RPM / WOT issue, the first thing id look at on your boat, is the prop the proper prop. Next, engine compression test and leak down test. Then there's timing and fuel delivery. Looking at the plugs can give you some insight into oil consumption.

[cltTige]

The 5.7's are notorious for burning/leaking oil. My parents still have a '99 suburban with 300k miles and its burned oil since ~150k no matter what we do to fix it. Despite this, it still runs great, it has no problems accelerating or in the high end RPM range. I would think the WOT/RPM and oil burning are different issues. But the oil pressure is throwing a wrench in things. A quick google search should give you the common problems/causes and where to look. Hopefully its just a bad gasket and not the rear main seal.

Mike why would a prop cause him to not reach 4/5k RPM? I get that it would cause him to be slower at WOT but not limit reaching it. So educate me here.

I would def follow Mike's advice on compression and leak down test. Timing could be off causing some of the WOT issue, but I think you would notice by it running rough at idle. have you noticed that? Someone smarter than me tell me/him if his problem could be as simple as the oil pressure sensor and how to test it?

[tigemech]

I would also hook up a remote oil pressure gauge to insure you dont have a bad sensor.

[Djimax]

You guys are great! Thanks for all the input! I will get a compression test and leak down done ASAP. The boat doesn’t idle rough at all. She purrs between 500 and 3500 rom (although she definitely feels like she’s working hard at that upper range limit). I will also hook up an external gauge, but I get solid pressure when the boat is above 1500 rpm, and even at startup - which is strange.

As for prop, I won’t deny the prop theory. I know I need a new prop. Mine has several “imperfections”. However, I also don’t understand why that would affect peak rpm. Top speed, sure. Hole shot, yup. But engine rpm? Confused here.


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[freeheel4life]

Im curious to hear what Mike has to say. Im no expert but I believe if he hasthe 1:1 Vdrove and is running a fairly large 4 blade it can load the engine so much that it cant turn it and that could keep it from achieving full throttle (over propped). Vice versa if one is underpropped thats how engines can over rev at WOT. At least thats my understanding, Mike knows better.

I also think it wouldnt be a terrible idea to verify RPM with a timing light to make sure its not actually a tach issue.

[Djimax]

Im curious to hear what Mike has to say. Im no expert but I believe if he hasthe 1:1 Vdrove and is running a fairly large 4 blade it can load the engine so much that it cant turn it and that could keep it from achieving full throttle (over propped). Vice versa if one is underpropped thats how engines can over rev at WOT. At least thats my understanding, Mike knows better.

I also think it wouldnt be a terrible idea to verify RPM with a timing light to make sure its not actually a tach issue.

My rpm is verified through both the onboard tach, and the perfect pass monitor. Not sure if they are both wrong or not, just figured I’d mention that.


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[Thegerman618]

if the prop is wrong size there may not be enough horsepower to turn the prop thus limiting the RPM to whatever the motor can turn the prop at. If this is a recent problem IE used to go to 4500 WOT before and now doesn't then something else is going on. I had a 350 MPI Merc in one of my boats and common issues that i can remember off the top of my head that reduced power significantly.

Spark Plugs- Get a decent set of plugs and wires.
Distributor Cap and Rotor- For some reason the factory ones are not sealed and can allow water intrusion or can get calcium or other build up and may run OK but a new cap and rotor can make a huge difference. Its was an easy $40 to spend annually and all always kept a spare on the boat.
Fuel Pumps- Mine did this exact thing when i lost the low pressure fuel pump, low power, low oil pressure, and hard starting when warm. BoatWakes probably knows off the top of his head what the fuel pressure should be at idle, I am guessing it was 45-50psi at idle and something like 65psi at WOT.
Last but not least- Prop Shaft alignment- While not common, i have read somewhere that most manufactures recommend having the alignment checked at least annually. The tolerance is not very tight but enough movement one way or the other could cause a bind and reduce power.
For what its worth my old Merc 350 loved the ACME 911 prop.

[chpthril]

Mike why would a prop cause him to not reach 4/5k RPM? I get that it would cause him to be slower at WOT but not limit reaching it. So educate me here.

Like tire diameter on a vehicle effects the speed at a given RPM, prop diameter and pitch will effect an engines ability to reach proper WOT and can even cause it to exceed a safe WOT RPM.

His gen v-drive could have come with either the 1:1 or the 1.46:1 gear. Take the 1:1 and put the wrong 4-blade prop on, and its a dog! Even with the proper number of blades, too high a pitch and the engine will not reach a desired WOT RPM.

[Djimax]

This is all very interesting... with information I’ve never heard before. Tomorrow I’ll be acid washing the hull, and I’ll check on prop info, as well as do my best to get a compression check.

So, the loss of a low pressure fuel pump can affect oil pressure?


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[chpthril]

Also note if the v-drive is blue or black. This along with the prop's dia and pitch are crucial.