Rookie Owner of 1992 Mariah 1900Z
 

Good morning! Super excited to be a new owner of a Mariah boat! It is a 1992 Mariah 1900Z with a Mercruiser 4.3 liter V6

Took her out for the first time this weekend and for the life of me cannot get her to plane out. does anyone know what the exact proper prop size is for this engine/boat?

It also seems to "backfire" like a car if you try to throttle too fast. Any help or insight would be greatly appreciated!

Re: Rookie Owner of 1992 Mariah 1900Z
 

One issue at a time. The back fire and lack of power are going to be tied to the same thing.
Do you know what the accelerator pump is and where it is located ?

Re: Rookie Owner of 1992 Mariah 1900Z
 

I know what it is, but I have not located it just yet. By the time we got off the water yesterday I was so frustrated that we parked and covered her up hoping that I can troubleshoot over this week. I am confidant that I can find it as I work on car engines quite a bit!

Re: Rookie Owner of 1992 Mariah 1900Z
 

I want to apologize for sounding so demeaning and there is zero doubt I was. I can be brash but I sure hate to KILL someone.
The pump must not be pumping that extra squirt of gas. Are you any good with carbs ? We are a dying breed you know.
I'd bet the diaphragm is no good.
Once again, sorry for being "brash"

Re: Rookie Owner of 1992 Mariah 1900Z
 

I did not feel you were being brash at all, so no worries! The carb was just rebuilt in May, all new spark plugs, full tune up and check. Past owner is a friend of mine and he said he had trouble getting it to plane when he first bought it, but then figured out the trick. Well, I can't figure out the trick and I have the backfire pop and he never did so I am really kind of lost on this one. I thank you for responding and trying to help a rookie out!

Re: Rookie Owner of 1992 Mariah 1900Z
 

I'm a rookie myself with Mariahs. Never owned an I/O motor before but have owned several big bass boats from Charger to a Gambler. All outboards.
My only real advantage over others on this site is I'm retired and have PLENTY of time to research stuff.
Is your motor reaching anywhere close to redline?
Is the popping only while accelling?
Have you checked the timing?

Re: Rookie Owner of 1992 Mariah 1900Z
 

No where close to redline. stays at about 100 for temp, tops out at 3000rpms but sounds like it is just running hard.

Yes, only pops when you try to floor it and just pops once, not continual. Kind of sounds like a car engine "missing or slipping" but the spark plugs are new and all tight so I kind of ruled that out.

No, I have not checked on the timing, would have to do some research on that, LOL. Seems like my boat ventures will be a lot of research and learning for a bit. I want to be comfortable with it so I am confidant that when I take it out I will not be stranded! Thank you again for the willingness to help!

Re: Rookie Owner of 1992 Mariah 1900Z
 

Roger, is yours a 2 or 4 barrel? Does it say LX anywhere? I found the service manual for it if you need it. Is it the spreadbore or a good ole Holley?

Re: Rookie Owner of 1992 Mariah 1900Z
 

Now you stumped me! It is a 1992 Mercruiser 4.3LX V6. Unfortunately I do not have the answer for the other questions but I think it is a r barrel and no idea if it is a Holley or a spreadbore. And the boat is sitting in my cousins driveway until I can get back over tomorrow or Wednesday to troubleshoot. You are awesome! Thanks again! Owners manual would be great for this rookie on a learning vurve

Re: Rookie Owner of 1992 Mariah 1900Z
 

NOT THE OWNERS MANUAL !! It is the repair manual for your engine. You can get the Mariah manual on here by being a contributor, which pays for the site.
(I know Shabah, I PROMISE I'll buy a membership on the first of next month !!!!)

Please make a contribution. I have literally over run this site with my aimless meanderings but I'm retired and really like TRYING to help y'all out. So, any monetary contributions will keep this open and for me, a place to irritate the old salts.

Re: Rookie Owner of 1992 Mariah 1900Z
 

When i made a contribution i got brand new captains chairs....[emoji12] lol


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Re: Rookie Owner of 1992 Mariah 1900Z
 

When i made a contribution i got brand new captains chairs....[emoji12] lol


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Re: Rookie Owner of 1992 Mariah 1900Z
 

I will also make a contribution after next payday! I need this site! My bad, I have the owner's manual but thank you for the service manual! I will be doing some troubleshooting this week in the evenings and hope to take her back out on Saturday. I will update as to what exactly we found and if we can get her to plane out!

Re: Rookie Owner of 1992 Mariah 1900Z
 

Hello new Mariah owner.

How many people did you have in the boat when you couldn't get it on plane? Was power smooth and did you feel thrust as you throttled up slowly?

Re: Rookie Owner of 1992 Mariah 1900Z
 

The first outing there was four of us, the second outing there was 7 of us. I talked to the prior owner and he said that he had the same problem at first and he simply did not have the prop all of the way down. I cannot imagine that would be the problem I am having unless the prop lowers really slowly. The boat accelerates well with throttle at about 1/4, slowly try to increase speed and it does a little bit, but then tops out at maybe 15mph and sounds like she is running hard. If you try to gun it from 1/4 to full, she let's out one backfire and I have to throttle down.

Re: Rookie Owner of 1992 Mariah 1900Z
 

Timing advance, or compression.... Time to go back to basics....

Compression test, check timing (including advance), change fuel filters (including any in the carb)....



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Re: Rookie Owner of 1992 Mariah 1900Z
 

All of this was just taken care of in May of this year. Prior owner had boat out 4 times this year and it was just fine, I am beginning to think it is simply me being a stupid rookie, but I am learning quite a bit about things on the boat!

Re: Rookie Owner of 1992 Mariah 1900Z
 

Above was a quote from a forum where someone had the exact same issues, turned out to be timing and filters.


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Re: Rookie Owner of 1992 Mariah 1900Z
 

Are you up on the use of trim while driving ? Do you know it's use ?

Re: Rookie Owner of 1992 Mariah 1900Z
 

Yes, I am familiar with the trim. We have been playing with it to see if we could get it to plane off. I am going over tonight to do some troubleshooting on the boat to check and see if the trim is actually trimming down all of the way or if it is getting stuck somewhere. It trims up perfectly

Re: Rookie Owner of 1992 Mariah 1900Z
 

Welcome to the Club Rodgers17! I am new to boating and Mariah's as well so it is nice to see I am not the only one. Everyone here has been GREAT! I feel your pain because even though I was told I really did not expect a boat to be so much work LOL. Every time I boated on a friends craft it worked great, gas tank was full, and all I had to do is bring beer. Wish I could help you but I am at best a lazy boy chair mechanic (over 10 steps and I do not do it). Keep us posted on what the problem is in the end.

Brian Belcher you crack me up!!

Re: Rookie Owner of 1992 Mariah 1900Z
 

So true!! Only had it for a week and have spent every waking hour researching and troubleshooting anything and everything, LOL. Brian has been great!

Re: Rookie Owner of 1992 Mariah 1900Z
 

Glad to hear Firestone even though I have no idea what you're taking about !
The irony is how hard and softly I tread as not to step on anyone's toes. I've been in the website thingy since the beginning, talking Netscape days. I was part of a very successful rock crawling website that is 18 years old only to see the Book of Faces shut it nearly down. I only hope I'm an asset here and like I said, if I don't know the answer, I'm pretty good at finding one. Got plenty of time to find it for you
Now, someone tell me how to resurrect my iPhone from a swim in the pool 3 days ago. Already gone through a box of rice

Re: Rookie Owner of 1992 Mariah 1900Z
 

Was the problem worse with 7 ppl or the same?

You could have prop slipping via the prop torque flow hub in the lower unit. This is designed to slip if the prop hits something solid. They can go bad but not very common.

Second thing to look at would be the engine coupler. It is mounted to the crankshaft and mates your driveshaft via a rubber sleeved splined. The rubber can break down and cause slippage but it is normally complete failure.

Since you can still gain speed I would say look and lower unit torque flow hub.

Re: Rookie Owner of 1992 Mariah 1900Z
 

Well, it was all in the prop after all. Switched from 15 diameter x 16 pitch 3 blade to a 15 diameter x 15 pitch 4 blade and she planes just fine no matter how many people are in the boat. Takes a tad longer with more people, but she sure does fly!!

Thanks again to everyone who had some input!

Re: Rookie Owner of 1992 Mariah 1900Z
 

That is great news. Be safe and enjoy your summer.