[rogers17]

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!

[Brian Belcher]

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 ?

[rogers17]

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!

[Brian Belcher]

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"

[rogers17]

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!

[Brian Belcher]

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?

[rogers17]

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!

[Brian Belcher]

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?

[rogers17]

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

[Brian Belcher]

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.